(WIP) Introducing the concept of EurekaService and ServiceChannel.

-- A service is the access point for registry access (both read/write)
-- A channel abstracts a protocol/command so that it provides a higher level abstraction of what is to be done for a command.

We can bikeshed on names but lets discuss the abstraction.
It is done at transport layer. Once the update observable completes, the acknowledgement is sent.