title: WebSocket transport not available. Install eventlet or gevent and gevent-websocket for improved performance
body: <p>I am using socket io and flask application.Everthing works except I always get this message.
  This is my initialization:</p>
  
  <pre><code>app = Flask(__name__)
  app.config['SECRET_KEY'] = APP_SECRET_KEY
  jwt = JWTManager(app)
  cors = CORS(app)
  app.config['CORS_HEADERS'] = 'Content-Type'
  # app.config['transports'] = 'websocket'
  socketio = SocketIO(app, cors_allowed_origins="*", async_mode='threading')
  
  socketio.run(app, debug=True)
  </code></pre>
  
  <p>What may cause this warning and what does it mean?</p>
  
  <p>The console looks like this:
  <a href="https://i.stack.imgur.com/3HEvj.png" rel="noreferrer"><img src="https://i.stack.imgur.com/3HEvj.png" alt="enter image description here"></a></p>
  
  <ul>
  <li>tried already to install gevent and eventlet and it didn't remove the message</li>
  </ul>