code: def connected_client(self):
          
          future = self.get_connected_client()
          cb = functools.partial(self._connected_client_release_cb, future)
          return ContextManagerFuture(future, cb)
docs: Returns a ContextManagerFuture to be yielded in a with statement.
  
          Returns:
              A ContextManagerFuture object.
  
          Examples:
              >>> with (yield pool.connected_client()) as client:
                      # client is a connected tornadis.Client instance
                      # it will be automatically released to the pool thanks to
                      # the "with" keyword
                      reply = yield client.call("PING")