Add unimplemented interface

[peterargue]

Closes: #???

Description

Possible approach to reduce boilerplate for unimplemented methods

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For contributor use:

• [ ] Targeted PR against master branch
• [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
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[bluesign]

This feels a bit wrong. ( according to https://github.com/onflow/flow-go-sdk/tree/master/access )

Each implementation (currently grpc and http) include the following parts: Base Client is the client that implements the client interface exposing all generic functionality. Client is the network specific client that exposes any additional options possible by the specific API implementation. Handler takes care of actual network communication implementing the communication protocol.

Shouldn't all functions in generic ( I think this means common subset ) implemented as exposed as interface ?

PS: I think this is somehow issue with initial implementation not this PR