code: protected void handshakeReceived(IoSession session,
  			HandshakeMessage handshakeMessage) {
  		log.debug("Received {}", handshakeMessage);
  		this.receivedHandshake = handshakeMessage;
  		Boolean handshakeCheck = this.checkHandshake();
  		if (handshakeCheck == null) {
  			return;
  		}
  
  		if (Boolean.FALSE.equals(handshakeCheck)) {
  			log.warn("Handshakes did not match.");
  			this._disconnect();
  		}
  		if (Boolean.TRUE.equals(handshakeCheck)) {
  			SubscriptionMessage msg = this.generateGenericSubscriptionMessage();
  			this.session.write(msg);
  			this.connected = true;
  		}
  	}
docs: Called when a handshake message is received from the aggregator.
  
  @param session
  the session on which the message arrived.
  @param handshakeMessage
  the received message.