Patent Publication Number: US-2020295888-A1

Title: System and method to assure data quality in distributed data collection pipeline

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present application relates to the field of distributed data pipelines and, in particular, to a distributed data pipeline that verifies the messages at one or more stages in the pipeline. 
     2. Description of the Related Art 
     A data pipeline is a network of components that can include, for example, data collection agents, a message queue, a computation engine, and storage resources. One issue with data pipelines is end-to-end message integrity. When a message is generated by a source and passed through different components in the network, the data can be transformed or lost. 
     Current-generation data pipelines focus on single message integrity (e.g., an integrity check with checksum), and do not consider message transformations and losses that can occur when passing through data pipelines. It is common for one message to be transformed into multiple messages, and for multiple messages to be merged into one message when passing a network component. 
     For example, the original message generated by a remote direct memory access (RDMA) agent (a type of data collection agent) contains multiple fields which are commonly transformed by an upstream proxy into three messages based on the application logic. It is also highly possible that some messages will not be received at the next receiving end (e.g., a message is not sent after the maximum number of retries by the sender, the message is lost by the sender, or the message is dropped by the receiver due to software bugs). 
     As a result, the destination has no conclusion on whether all messages from the source have been successfully received (although the destination can determine that the messages that have been received have not been corrupted). Moreover, message-level data quality is different from the packet-level data quality. It is common for packets to be successfully transmitted to a receiver that cannot construct the messages due to resource limitations (e.g., CPU limit and Memory limit). 
     Thus, since it is not unusual for the message transformation process to fail due to various reasons (e.g., a received message is corrupted, a receiver suffers CPU or memory shortage, and a conversion software version mismatch), and since data transformations and losses can occur in any component of the data pipeline, there is a need to assure data quality on the destination side. 
     SUMMARY 
     The present disclosure provides a distributed data pipeline that assures end-to-end data quality by verifying the messages at one or more stages in the pipeline. A component of a distributed data pipeline includes a memory and a processor coupled to the memory. The processor to read information from and write information to the memory to determine a number of messages that should have been received, determine a number of messages that were actually received, and determine whether the number of messages that were actually received match the number of messages that should have been received. The number of messages that should have been received is generated by an upstream component using a predefined transformation function. The processor to also generate a lost message signal when the number of messages that were actually received does not match the number of messages that should have been received. 
     The present disclosure also provides a method of operating a component of a distributed data pipeline that includes determining a number of messages that should have been received, determining a number of messages that were actually received, and determining whether the number of messages that were actually received combined with an error tolerance number is less than the number of messages that should have been received. The method also includes generating a lost message signal when the number of messages that were actually received combined with the error tolerance number is less than the number of messages that should have been received. 
     The present disclosure further provides a non-transitory computer-readable storage medium having embedded therein program instructions, which when executed by a processor causes the processor to execute a method of operating a component in a distributed data pipeline. The method includes determining a number of messages that should have been received, determining a number of messages that were actually received, and determining whether the number of messages that were actually received combined with an error tolerance number is less than the number of messages that should have been received. The method also includes generating a lost message signal when the number of messages that were actually received combined with the error tolerance number is less than the number of messages that should have been received. 
     The present disclosure additionally includes a distributed data pipeline that includes a source component to generate a number of messages, transmit the number of messages, determine a number of messages that were transmitted, and transmit a notification that indicates the number of messages that should have been received from the number of messages that were transmitted. The distributed data pipeline also includes a first-level component coupled to the source component. The first level component to receive the number of messages, determine a number of messages that should have been received from the notification, and determine a number of messages that were actually received. The first level component to also determine whether the number of messages that were actually received combined with an error tolerance number is less than the number of messages that should have been received. The first level component to further generate a lost message signal when the number of messages that were actually received combined with the error tolerance number is less than the number of messages that should have been received. 
     A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description and accompanying drawings which set forth an illustrative embodiment in which the principals of the invention are utilized. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating an example of a distributed data pipeline  100  in accordance with the present invention. 
         FIG. 2  is a flow chart illustrating an example of a method  200  of operating a component of a distributed data pipeline in accordance with the present invention. 
         FIG. 3  is a flow chart illustrating an example of a method  300  of operating an intermediate component of a distributed data pipeline in accordance with the present invention. 
         FIG. 4  is a flow chart illustrating an example of a method  400  of operating an intermediate component of a distributed data pipeline in accordance with the present invention. 
         FIGS. 5A-5B  are a flow chart illustrating an example of a method  500  of operating a distributed data pipeline in accordance with the present invention. 
     
    
    
     A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description and accompanying drawings which set forth an illustrative embodiment in which the principals of the invention are utilized. 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a diagram that illustrates an example of a distributed data pipeline  100  in accordance with the present disclosure. As described in greater detail below, the present disclosure guarantees that messages generated at a source are reliably received at a destination by tracking the number of messages sent to and received by each of the components of the pipeline as the messages move through the distributed data pipeline. 
     The following terminologies are defined to aid in the understanding of the present invention. 
     Distributed Data Pipeline: A distributed system that collects data from the source and sends original or transformed data to the destination. It consists of multiple networked components. 
     Message: A message is data with a header. A packet, in turn, is a portion of the data with a header. In message switching, a router must wait for all of the data to be received before forwarding the data, whereas in packet switching a router can forward data as soon as each portion of the data has been received. 
     Data Quality: The amount of data received on the destination compared with the data sent from the source. 
     Source: The beginning component of a data pipeline which generates messages. There could be multiple sources in a data pipeline. 
     Sink: The ending component of a data pipeline which consumes data generated from the source. There could be multiple sinks in a data pipeline. 
     Batching Mode: Messages are not sent immediately from a component after being generated or received. Instead, messages are sent after accumulating to a certain number of messages or after a fixed period of time. 
     Streaming Mode: A message is sent immediately from a component after being generated or received. 
     Transformation Functions f(*) and g(*): Functions that takes a scalar or vector of integer numbers, mapping the number of received messages to the number of messages to be sent. 
     Epsilon(*): A predefined integer that determines whether there is a loss event. For practical sake, it is a value ranging from 0 to a specific fraction of the number of received messages. Epsilon(*) is actually an error tolerance number or a predefined fault tolerance level. If it is 0, it indicates zero tolerance on message loss. 
     Referring to  FIG. 1 , distributed data pipeline  100  includes a source component  110  and a number of first-level intermediate components  120  that are coupled to the source component  110  by way of a number of message transmission channels  122 A and a number of notification transmission channels  122 B. In the  FIG. 1  example, the number of first-level intermediate components  120  is illustrated with two first-level intermediate components  120 A and  120 B that are each coupled to the source component  110  by way of a message transmission channel  122 A and a notification transmission channel  122 B. 
     Distributed data pipeline  100  also includes a number of second-level intermediate components  130  that are coupled to the first-level intermediate components  120  by way of a number of message transmission channels  132 A and a number of notification transmission channels  132 B. In the  FIG. 1  example, the number of second-level intermediate components  130  is illustrated with a single second-level intermediate component  130  that is coupled to each of the first-level intermediate components  120 A and  120 B by way of a message transmission channel  132 A and a notification transmission channel  132 B. 
     Distributed data pipeline  100  further includes a number of sink components  140  that are coupled to the number of second-level intermediate components  130  by way of a number of message transmission channels  142 A and a number of notification transmission channels  142 B. In the  FIG. 1  example, the number of sink components  140  is illustrated with two sink components  140 A and  140 B that are each coupled to the second-level intermediate component  130  by way of a message transmission channel  142 A and a notification transmission channel  142 B. 
     As shown in  FIG. 1 , each of the components includes a processor  150  and a memory  152  that is coupled to the processor  150 . The processor  150  reads information from and writes information to the memory  152  to operate the component. In some cases, an intermediate component may be implemented in logic and not require a standalone processor and memory. In addition, although two levels of intermediate components have been illustrated, any number of levels of intermediate components can alternately be used. 
     As further shown in  FIG. 1 , the first-level intermediate components  120  and the second-level intermediate component  130  of distributed data pipeline  100  can be sorted as a directed acyclic graph (DAG) based on the data flow from source(s) to sink(s). A directed acyclic graph (DAG) is a graph that illustrates a sequence of tasks where there is no possible way for the sequence to complete a task and then somehow loop back again to the same task. 
       FIG. 2  shows a flow chart that illustrates a first example of a method  200  of operating a component of a distributed data pipeline in accordance with the present invention. As shown in the  FIG. 2  example, method  200  begins at  210  by determining a number of messages that should have been received. The number of messages that should have been received is generated by an upstream component using a predefined transformation function. After this, method  200  moves to  212  to determine a number of messages that were actually received. 
     Next, method  200  moves to  214  to determine whether the number of messages that were actually received combined with an error tolerance number is less than the number of messages that should have been received. The error tolerance number is the predefined fault tolerance threshold or level. For example, if the error tolerance number is 0, it indicates zero tolerance on message loss. In other words, the number of messages that should have been received and the number of messages that were actually received must match. One lost message causes the combined number to be less than the number of messages that should have been received. If the error tolerance number is 1, one lost message does not cause the combined number to be less than the number of messages that should have been received. 
     Following this, method  200  moves to  216  to generate a lost message signal when the number of messages that were actually received combined with the error tolerance number is less than the number of messages that should have been received. When the error tolerance number is 0, the lost message signal is generated when the number of messages that should have been received and the number of messages that were actually received do not match. 
       FIG. 3  shows a flow chart that illustrates an example of a method  300  of operating an intermediate component of a distributed data pipeline in accordance with the present invention. As shown in the  FIG. 3  example, method  300  begins at  310  by receiving a number of incoming messages, and a notification that indicates the number of incoming messages that were sent. The number of messages that should have been received in  210  of  FIG. 2  can be determined from the number of incoming messages that were sent. 
     The messages can be sent via a message transmission channel, such as message transmission channel  122 A, and the notification can be sent via a notification transmission channel, such as notification transmission channel  122 B. Alternately, the notification with the number of incoming messages that were sent can be included in a header of an incoming message. 
     After this, method  300  moves to  312  to determine a number of incoming messages that were actually received. In the present example, the number of incoming messages that were actually received is determined by counting the incoming messages as the incoming messages are received. Next, method  300  moves to  314  to determine whether the number of incoming messages that were actually received combined with an error tolerance number is less than the number of incoming messages that should have been received. 
     Following this, method  300  moves to  316  to generate a lost message signal when the number of incoming messages that were actually received combined with the error tolerance number is less than the number of incoming messages that should have been received. Next, method  300  moves to  318  transform the incoming messages that were actually received into a number of outgoing messages. In many cases, following the transformation, the number of outgoing messages is different from the number of incoming messages that were actually received. 
     After the transformation, method  300  moves to  320  to transmit the number of outgoing messages, and then to  322  to determine a number of outgoing messages that were transmitted. In the present example, the number of outgoing messages that were transmitted is determined by counting the outgoing messages as the outgoing messages are transmitted. 
     Following this, method  300  moves to  324  to transmit an outgoing notification that indicates the number of outgoing messages that were transmitted as a number of outgoing messages that were sent, and further indicates whether the lost message signal was generated. Thus, method  300  determines whether any incoming messages were lost, and provides a count to the next component in the pipeline to determine whether any of the outgoing messages were lost and not received. 
       FIG. 4  shows a flow chart that illustrates an example of a method  400  of operating an intermediate component of a distributed data pipeline in accordance with the present invention. As shown in the  FIG. 4  example, method  400  begins at  410  by receiving a number of incoming messages. After this, method  400  moves to  412  to transform the number of incoming messages into a number of outgoing messages. In many cases, the number of incoming messages and the number of outgoing messages are different. 
     After the transformation, method  400  moves to  414  to transmit the number of outgoing messages, and then to  416  to determine the number of outgoing messages that were transmitted. In the present example, the number of outgoing messages that were transmitted is determined by counting the outgoing messages as the outgoing messages are transmitted. 
     After this, method  400  moves to  418  to receive a notification that indicates the number of outgoing messages that were actually received by a component. Next, method  400  moves to  420  to determine whether the number of outgoing messages that were actually received combined with an error tolerance number is less than the number of outgoing messages that were actually transmitted. 
     Following this, method  400  moves to  422  to generate a lost message signal when the number of outgoing messages that were actually received combined with an error tolerance number is less than the number of outgoing messages that were actually transmitted. 
       FIGS. 5A-5B  show a flow chart that illustrates an example of a method  500  of operating a distributed data pipeline in accordance with the present invention. As shown in  FIGS. 5A-5B , method  500  begins at  510  by generating a number of source messages at a source node, such as source component  110 . The messages can be generated at a fixed or variable rate. 
     Method  500  next moves to  512  to transmit, over a first time period, the number of source messages to a number of first-level intermediate nodes, such as the first-level intermediate components  120 A and  120 B, by way of a message transmission channel. During the first time period, method  500  also counts the number of source messages that are sent to the first-level intermediate nodes. 
     In addition, at the end of the first time period, method  500  further transmits a source notification to the first-level intermediate nodes by way of a notification transmission channel that indicates the total number of source messages that were transmitted during the first time period. The source messages and notifications can be transmitted by the source node. 
     With respect to  FIG. 1 , the source component  110  transmits the source messages to the first-level intermediate components  120 A and  120 B by way of the message transmission channels  122 A over a first time period, counts the number of source messages that have been sent to the first-level intermediate components  120 A and  120 B during the first time period, and transmits a source notification to the first-level intermediate components  120 A and  120 B by way of the notification transmission channels  122 B that indicates the total number of messages that have been sent. 
     Method  500  next moves to  514  to receive the source messages and notifications sent from the source node at the first-level intermediate nodes. With respect to  FIG. 1 , the first-level intermediate components  120 A and  120 B receive the messages from the source component  110  by way of the message transmission channels  122 A, and the notification from the source component  110  indicating the total number of source messages that have been sent by way of the notification transmission channels  122 B. 
     Following this, method  500  moves to  516  to count the actual number of received source messages, referred to as X′, and then determine whether the actual number of received source messages X′ combined with an error tolerance number is less than the total number of sent messages, referred to as X, as indicated in the source notification. The counting and determining can be performed with the first-level intermediate nodes. If X′, or alternately X′+Epsilon(*) (the error tolerance number), is less than X, the first-level intermediate nodes detect a message loss event. 
     With respect to  FIG. 1 , the first intermediate components  120 A and  120 B count the number of source messages that have been received by way of the message transmission channels  122 A, and determine whether the number of source messages that have been received by way of the message transmission channels  122 A combined with an error tolerance number is less than the total number of source messages that were sent as indicated by the source notification received by way of the notification transmission channels  122 B. 
     Following this, method  500  moves to  518  to generate a lost message signal when the number of source messages that were actually received combined with the error tolerance number is less than the number of source messages that were sent and should have been received. Next, method  500  moves to  520  where each first-level intermediate node transforms the source messages that were actually received into a number of first-level messages by passing, modifying, reassembling, or even dropping the received source messages, depending on the transformation function of the first-level intermediate node. In many cases, the number of source messages that were actually received and the number of first-level messages are different. 
     For example, one first-level intermediate node may transform a single source message into a five first-level messages using a transformation function represented as f(*), while another first-level intermediate node may transform a single source message into ten first-level messages using a transformation function represented as g(*). 
     With respect to  FIG. 1 , each of the first-level intermediate components  120 A and  120 B transforms the source messages that were actually received into a number of first-level messages by passing the received source messages, modifying the received source messages, or generating new source messages based on the received source messages, depending on the transformation function of the intermediate component. 
     Method  500  next moves to  522  where, over a second time period, method  500  transmits the number of first-level messages to a number of second-level intermediate nodes, such as the second-level intermediate component  130 , by way of a message transmission channel. During the second time period, method  500  also counts the number of first-level messages that have been sent to the second-level intermediate nodes. 
     In addition, at the end of the second time period, method  500  transmits a first-level notification to the second-level intermediate nodes by way of a notification transmission channel that indicates the total number of first-level messages that were transmitted during the second time period. Further, the first-level notification can indicate whether any message lost events have occurred. The first-level messages and notifications can be transmitted by the first-level intermediate nodes. 
     With respect to  FIG. 1 , the first-level intermediate components  120 A and  120 B transmit the first-level messages to the second-level intermediate component  130  over the message transmission channels  132 A, count the number of first-level messages that have been sent to the second-level intermediate component  130 , and transmit a first-level notification to the second-level intermediate component  130  over the notification transmission channels  132 B that indicates the total number of messages that have been sent as well as whether any message lost events occurred. 
     Method  500  next moves to  524  to receive the first-level messages and notifications sent from the first-level intermediate nodes at the second-level intermediate nodes. With respect to  FIG. 1 , the second-level intermediate component  130  receives the first-level messages from the first-level intermediate components  120 A and  120 B by way of the message transmission channels  132 A, and the first-level notifications from the first-level intermediate components  120 A and  120 B indicating the total number of first-level messages that have been sent by way of the notification transmission channel  132 B. 
     Following this, method  500  moves to  526  to count the actual number of received first-level messages, referred to as Y′, and then determine whether the actual number of received first-level messages Y′ combined with an error tolerance number is less than the total number of sent messages, referred to as Y, as indicated in the first-level notifications. The counting and determining can be performed with the second-level intermediate nodes. If Y′, or alternately Y′+Epsilon(*) (the error tolerance number), is less than Y, the second-level intermediate nodes detect a message loss event. 
     With respect to  FIG. 1 , the second intermediate component  130  determines the number of first-level messages that have been received from the first-level intermediate node  120 A by way of the message transmission channel  132 A, and determines whether the number of first-level messages that have been received from the first-level intermediate node  120 A by way of the message transmission channel  132 A combined with an error tolerance number is less than the total number of first-level messages that were sent as indicated by the first-level notification received from the first-level intermediate node  120 A by way of the notification transmission channel  132 B. 
     In addition, the second intermediate component  130  separately determines the number of first-level messages that have been received from the first-level intermediate node  120 B by way of the message transmission channel  132 A, and determines whether the number of first-level messages that have been received from the first-level intermediate node  120 B by way of the message transmission channel  132 A combined with an error tolerance number is less than the total number of first-level messages that were sent as indicated by the first-level notification received from the first-level intermediate node  120 B by way of the notification transmission channel  132 B. 
     Next, method  500  moves to  528  to generate a lost message signal when the number of first-level messages that were actually received combined with the error tolerance number is less than the number of first-level messages that were sent and should have been received. Following this, method  500  moves to  530  where each second-level intermediate node transforms the first-level messages that were actually received into a number of second-level messages by passing, modifying, reassembling, or even dropping the received first-level messages, depending on the transformation function of the node. In many cases, the number of first-level messages that were actually received and the number of second-level messages are different. 
     For example, a second-level intermediate node may transform five first-level messages from one first-level intermediate node into ten second-level messages using a transformation function represented as f(**), and may transform 10 first-level messages from one first-level intermediate node into 20 second-level messages using a transformation function represented as g(**). The transformation function can be a vector of functions when, as in the present example, messages are sent to multiple components. 
     With respect to  FIG. 1 , the second-level intermediate component  130  transforms the first-level messages into second-level messages by passing the received first-level messages, modifying the received first-level messages, merging the received first-level messages, or generating new second-level messages based on the received first-level messages, depending on the transformation function of the intermediate component. 
     Method  500  next moves to  532  where, over a third time period, method  500  transmits the number of second-level messages to a number of third-level sink nodes, such as the third-level sink components  140 A and  140 B, by way of a message transmission channel. During the third time period, method  500  also counts the number of second-level messages that have been sent to the third-level sink nodes. 
     In addition, at the end of the third time period, method  500  transmits a second-level notification to the third-level sink nodes by way of a notification transmission channel that indicates the total number of second-level messages that were transmitted during the third time period. Further, the second-level notification can indicate whether any first-level messages were lost. The second-level messages and notifications can be transmitted by the second-level nodes. With respect to  FIG. 1 , second-level intermediate component  130  transmits the second-level messages to the third-level sink components  140 A and  140 B by way of the message transmission channels  142 A over the third time period, and the second-level notification by way of the notification transmission channels  142 B. 
     Method  500  next moves to  534  to receive the second-level messages and notifications sent from the second-level intermediate node at the third-level sink nodes, which do not forward or send messages to other components. With respect to  FIG. 1 , the third-level sink components  140 A and  140 B receive the second-level messages from the second-level intermediate component  130  by way of the message transmission channels  142 A, and the second-level notifications from second-level intermediate component  130  indicating the total number of second-level messages that have been sent by way of the notification transmission channels  142 B. 
     Following this, method  500  moves to  536  to count the actual number of received second-level messages, referred to as Z′, and then determine whether the actual number of received second-level messages Z′ combined with an error tolerance number is less than the total number of second-level messages, referred to as Z, that were sent as indicated by the second-level notification. The counting and determining can be performed with the third-level sink nodes. If Z′ (or alternately Z′+Epsilon(*)) is less than Z, the third-level sink nodes detect a message loss event. 
     Next, method  500  moves to  538  to generate a lost message signal when the number of second-level messages that were actually received combined with the error tolerance number is less than the number of second-level messages that were sent and should have been received. Following this, method  500  moves to  540  where each third-level sink node transforms the second-level messages that were actually received into a number of destination-specific messages by passing, modifying, reassembling, or even dropping the received second-level messages, depending on the transformation function of the node. In many cases, the number of second-level messages that were actually received and the number of destination-specific messages are different. 
     Thus, the third-level sink nodes and sink components  140 A and  140 B receive the messages sent by the source node and source component  110 , and additionally receive and determine whether any of the messages have been lost as the messages moved through the distributed data pipeline. As a result, if any data is missing in the pipeline, the present invention can precisely locate where the data was lost. 
     Further, the present approach applies for both batch mode and streaming mode. The fixed period T can be substituted by a sliding window or a water mark in streaming mode. The expected number of messages can also be packed into the header of a message which reuses the data path instead of using separated notification channel. Alternately, a receiving node can notify its immediate upper level sender as to how many messages have been successfully received, where the sender compares the number with the number of messages actually sent. 
     In summary, a transformation function is defined at each node or network component. In addition, each node or network component compares the number of actually received messages with the expected number from one or more parent nodes to detect a message loss event and locate where the message loss event occurred. Through this approach of detecting lost messages at each step in the pipeline, the data quality from the source(s) to sink(s) in a distributed data pipeline can be assured. 
     All nodes are loosely synchronized and a small number Epsilon(*) can be added when comparing the actually received number of messages and the expected number. The transformation function can be explicitly defined based on concrete business logic or implicitly implied by counting the number of successfully sent messages. The components of the data pipeline can be either open-source or close-source software. 
     In the whole pipeline, the number of messages generated by a source is audited at each component of the pipeline. Using the above described audit method, a loss event can be efficiently detected and located. In the audit method above, the transformation functions are predefined to determine the number of messages expected to be received at the next level of component. The predefined function can cover one-to-one, one-to-many and many-to-many transmission relationships. In addition, the message loss event(s) are detected and the component(s) that causes the loss is located by comparing actually received number of messages and the expected number of messages at each component of a distributed data pipeline. 
     The technical solutions in the embodiments of the present application have been clearly and completely described in the prior sections with reference to the drawings of the embodiments of the present application. It should be noted that the terms “first”, “second”, and the like in the description and claims of the present invention and in the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific sequence or order. It should be understood that these numbers may be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in orders other than those illustrated or described herein. 
     The functions described in the method of the present embodiment, if implemented in the form of a software functional unit and sold or used as a standalone product, can be stored in a computing device readable storage medium. Based on such understanding, a portion of the embodiments of the present application that contributes to the prior art or a portion of the technical solution may be embodied in the form of a software product stored in a storage medium, including a plurality of instructions for causing a computing device (which may be a personal computer, a server, a mobile computing device, or a network device, and so on) to perform all or part of the steps of the methods described in various embodiments of the present application. The foregoing storage medium includes: a USB drive, a portable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, an optical disk, and the like, which can store program code. 
     The various embodiments in the specification of the present application are described in a progressive manner, and each embodiment focuses on its difference from other embodiments, and the same or similar parts between the various embodiments may be referred to another case. The described embodiments are only a part of the embodiments, rather than all of the embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application without departing from the inventive skills are within the scope of the present application. 
     The above description of the disclosed embodiments enables a person skilled in the art to make or use the present application. Various modifications to these embodiments are obvious to a person skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but the broadest scope consistent with the principles and novel features disclosed herein.