readMessage
Reads and deserializes a JSON-RPC message from the input buffer.
The method attempts to read lines from the buffer until a valid JSONRPCMessage is successfully deserialized. Blank lines are ignored, and if a deserialization error occurs, the method attempts to recover and process the message.
Recovery involves attempting to parse from the first detected JSON object in the line when an error is encountered during deserialization.
Return
A deserialized JSONRPCMessage if successfully processed; otherwise, null if the input buffer is exhausted or no valid message is found.