Add idiomatic documentation to Go, Java, Python, and Rust clients

clients/python/src/mxgateway/client.py

@@ -25,6 +25,7 @@ class GatewayClient:
         stub: Any,
         channel: grpc.aio.Channel | None = None,
     ) -> None:
+        """Initialize the client with resolved options and a gRPC stub."""
         self.options = options
         self.raw_stub = stub
         self._channel = channel
@@ -63,9 +64,11 @@ class GatewayClient:
         )
 
     async def __aenter__(self) -> "GatewayClient":
+        """Return self to support ``async with`` usage."""
         return self
 
     async def __aexit__(self, *_exc_info: object) -> None:
+        """Close the client when leaving an ``async with`` block."""
         await self.close()
 
     async def close(self) -> None:
@@ -99,6 +102,7 @@ class GatewayClient:
         return Session(client=self, session_id=reply.session_id, open_reply=reply)
 
     async def open_session_raw(self, request: pb.OpenSessionRequest) -> pb.OpenSessionReply:
+        """Send an `OpenSession` RPC and return the raw reply."""
         reply = await self._unary("open session", self.raw_stub.OpenSession, request)
         ensure_protocol_success("open session", reply.protocol_status, reply)
         return reply
@@ -107,11 +111,13 @@ class GatewayClient:
         self,
         request: pb.CloseSessionRequest,
     ) -> pb.CloseSessionReply:
+        """Send a `CloseSession` RPC and return the raw reply."""
         reply = await self._unary("close session", self.raw_stub.CloseSession, request)
         ensure_protocol_success("close session", reply.protocol_status, reply)
         return reply
 
     async def invoke_raw(self, request: pb.MxCommandRequest) -> pb.MxCommandReply:
+        """Send an `Invoke` RPC and return the raw reply."""
         reply = await self._unary("invoke", self.raw_stub.Invoke, request)
         ensure_protocol_success("invoke", reply.protocol_status, reply)
         return reply