How to use the uwsgi.websocket_send function in uWSGI

""" % (ws_scheme, env['HTTP_HOST'])
    elif env['PATH_INFO'] == '/foobar/':
        uwsgi.websocket_handshake(env['HTTP_SEC_WEBSOCKET_KEY'], env.get('HTTP_ORIGIN', ''))
        print "websockets..."
        while True:
            msg = uwsgi.websocket_recv_nb()
            if msg:
                queue.put(msg)
            else:
                try:
                    wait_read(uwsgi.connection_fd(), 0.1)
                except gevent.socket.timeout:
                    try:
                        msg = queue.get_nowait()
                        uwsgi.websocket_send(msg)
                    except Exception:
                        pass
    return ""

# add a 4 seconds timer to manage ping/pong
        asyncio.get_event_loop().call_later(4, ws_recv_msg, myself)

        # add a coroutine for redis messages
        f = GreenFuture()
        asyncio.Task(redis_wait(subscriber, f))

        # switch again
        f.greenlet.parent.switch()

        while True:
            # any redis message in the queue ?
            if f.done():
                msg = f.result()
                uwsgi.websocket_send("[%s] %s" % (time.time(), msg))
                # restart coroutine
                f = GreenFuture()
                asyncio.Task(redis_wait(subscriber, f))
            if myself.has_ws_msg:
                myself.has_ws_msg = False
                msg = uwsgi.websocket_recv_nb()
                if msg:
                    asyncio.Task(redis_publish(connection, msg))
            # switch again
            f.greenlet.parent.switch()

def _send_job(self):
        while True:
            data = self.send_queue.get()
            uwsgi.websocket_send(data, request_context=self.ctx)

uwsgi.suspend()
            fd = uwsgi.ready_fd()
            if fd > -1:
                if fd == websocket_fd:
                    msg = uwsgi.websocket_recv_nb()
                    if msg:
                        r.publish('foobar', msg)
                elif fd == redis_fd:
                    msg = channel.parse_response()
                    print(msg)
                    # only interested in user messages
                    t = 'message'
                    if sys.version_info[0] > 2:
                        t = b'message'
                    if msg[0] == t:
                        uwsgi.websocket_send("[%s] %s" % (time.time(), msg))
            else:
                # on timeout call websocket_recv_nb again to manage ping/pong
                msg = uwsgi.websocket_recv_nb()
                if msg:
                    r.publish('foobar', msg)

def keepalive():
        """Keep the websocket connection alive (called every 30 seconds)."""
        print('PING/PONG...')
        try:
            uwsgi.websocket_recv_nb()
            connection.add_timeout(30, keepalive)
        except OSError as error:
            print(error)
            sys.exit(1) # Kill process and force uWSGI to Respawn

    keepalive()

    while True:
        for method_frame, _, body in channel.consume(queue_name):
            try:
                uwsgi.websocket_send(body)
            except OSError as error:
                print(error)
                sys.exit(1)  # Force uWSGI to Respawn
            else:
                # acknowledge the message
                channel.basic_ack(method_frame.delivery_tag)

def keepalive():
        """Keep the websocket connection alive (called each minute)."""
        print('PING/PONG...')
        try:
            uwsgi.websocket_recv_nb()
            connection.add_timeout(30, keepalive)
        except OSError as error:
            print(error)
            sys.exit(1) # Kill process and force uWSGI to Respawn

    keepalive()

    while True:
        for method_frame, _, body in channel.consume(queue):
            try:
                uwsgi.websocket_send(body)
            except OSError as error:
                print(error)
                sys.exit(1) # Kill process and force uWSGI to Respawn
            else:
                # acknowledge the message
                channel.basic_ack(method_frame.delivery_tag)

def send(self, message, binary=None):
        try:
            uwsgi.websocket_send(message)
        except IOError, e:
            self.close()
            raise WebSocketError(e)

def send_message(type, content):
    uwsgi.websocket_send(json.dumps({
        'type': type,
        'content': content,
    }))