code: protected void handshakeMessageReceived(IoSession session,
        HandshakeMessage handshakeMessage) {
      log.debug("Received {}", handshakeMessage);
      this.receivedHandshake = handshakeMessage;
      Boolean handshakeCheck = this.checkHandshake();
      if (handshakeCheck == null) {
        return;
      }
      if (Boolean.TRUE.equals(handshakeCheck)) {
        this.canSendSamples = true;
        for (ConnectionListener listener : this.connectionListeners) {
          listener.readyForSamples(this);
        }
      } else if (Boolean.FALSE.equals(handshakeCheck)) {
        log.warn("Handshakes did not match.");
        this._disconnect();
      }
  
    }
docs: Verifies the received and notifies listeners if the connection is ready to
  send samples. If the handshake was invalid, disconnects from the
  aggregator.
  
  @param session
  the session that received the message
  @param handshakeMessage
  the message that was received.