code: public final void removeWebSocketPushListener(final String sessionId) {
  
          final WebSocketPushListener removed = sessionIdWsListeners
                  .remove(sessionId);
          wsListeners.remove(removed);
          wsListener = wsListeners.peek();
      }
docs: removes the WebSocket listener added for this WebSocket session
  
  @param sessionId
  the unique id of WebSocket session
  @since 2.1.0
  @author WFF