question: protected void unexpectedMessage ( int transactionId , MessageType type , Channel channel ) { String message = "Received unexpected message: " + type ; logger . warn ( "[{}->{}] {}" , new Object [ ] { getLocalNodeIdString ( ) , getRemoteNodeIdString ( ) , message } ) ; channel . writeAndFlush ( getError ( transactionId , new SyncException ( message ) , type ) ) ; }
target:  Send an error to the channel indicating that we got an unexpected message for this type of RPC client