code: void handleRequest(ByteBuf buffer) {
      long requestId = buffer.readLong();
  
      try {
        Object request = readRequest(buffer);
        HandlerHolder handler = handlers.get(request.getClass());
        if (handler != null) {
          handler.context.executor().execute(() -> handleRequest(requestId, request, handler));
        } else {
          handleRequestFailure(requestId, new SerializationException("unknown message type: " + request.getClass()), this.context);
        }
      } catch (SerializationException e) {
        handleRequestFailure(requestId, e, this.context);
      } finally {
        buffer.release();
      }
    }
docs: Handles a request.