Introduced the concept of context while executing a request chain so that a developer doesn't need to care about where to put data while handling request. Before, it was confusing if the data needed to be on the request.data or response.data. Now, just put it on the context and it will move forward. Once done from a processor, the context is added to response.data and thus available to the consumer. That allows removing the need for a node to know about its predecessor or successor. It only needs to put data in the context.