title: Can i detect 'connection lost' in websockets using Python3.6 Sanic?
body: <p>can i detect ( if yes how?) when my Python3.6 Sanic Web Server lost connection with client application (example: user closes web browser or network fails, etc...)</p>
  
  <pre>
  
  from sanic import Sanic
  import sanic.response as response
  
  app = Sanic()
  
  
  @app.route('/')
  async def index(request):
      return await response.file('index.html')
  
  
  @app.websocket('/wsgate')
  async def feed(request, ws):
      while True:
          data = await ws.recv()
          print('Received: ' + data)
          res = doSomethingWithRecvdData(data)
          await ws.send(res)
  
  
  
  if __name__ == '__main__':
      app.run(host="0.0.0.0", port=8000, debug=True)
  
  </pre>