gNMI Subscribe Client Functionality (#196)
gNMI Subscribe Client Functionality (#196)

* ONCE, STREAM and POLL working

* Refactored for unit testing

* Added io.EOF check for stream

* Better refactor for mock and testing

* Clarify POLL Mode Error

* Removed capital letters from error messages

* Refactored common gnmi_subscribe code

* Changed 0 to -1 in subscriptionMode

* Added const UNKNOWN to represent unknown encoding format or unknown
subscription mode

* Removed const UNKNOWN
Refactored print into pollInput
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