Implement generic `Client` that can communicate with the remote server via
protobuf `Message`'s. The client can uniformly execute any protobuf RPC
on the remote server using any of the supported transport protocols.
Currently only gRPC protocol is supported.
Additionally implement helpful functions to transmit messages by one of the
flow types: unary, client- or server-side stream.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Define `Message` interface of the generic protobuf message. In the initial
implementation, the message should be convertible to and from related gRPC
message.
Implement encoding functions over the `Message` that can:
* unmarshal the `Message` via related gRPC message;
* decode the `Message` from JSON format via related gRPC message;
* encode the `Message` to JSON.
Implement nested `test` package for testing the implementation.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Implement gRPC client that can uniformly execute any RPC on the remote
server. In the primary implementation, the client is a thin wrapper over
gRPC client connection that is required to create the client. In the future,
it is planned to expand the library with convenient functionality.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
