e websocket message type (text, binary, pong) may be added to each Session. I.e. a maximum
 of one message handler to handle incoming text messages a maximum of one message handler for
 handling incoming binary messages, and a maximum of one for handling incoming pong
 messages. For further details of which message handlers handle which of the native websocket
 message types please see <a href="../../javax/websocket/MessageHandler.Whole.html" title="interface in javax.websocket"><code>MessageHandler.Whole</