@Override
    public void destroy() {
        tunnels.shutdown();
    }
Called whenever the JavaScript Guacamole client makes a write request.
This function should in general not be overridden, as it already
contains a proper implementation of the write operation.

@param request
    The HttpServletRequest associated with the write request received.
    Any data to be written will be specified within the body of this
    request.

@param response
    The HttpServletResponse associated with the write request received.

@param tunnelSessionToken
    The tunnel-specific session token of the HTTP tunnel to write to,
    as specified in the write request. This tunnel must have been created
    by a previous call to doConnect().

@throws GuacamoleException
    If an error occurs while handling the write request.
guacamole-common/src/main/java/org/apache/guacamole/servlet/GuacamoleHTTPTunnelServlet.java