code: def trace(self, data, callback=None):
          
  
          if self._push_channel is None:
              return
  
          self._push_channel.trace(data, callback=callback)
docs: Trace data asynchronously.
  
          If no one is listening for traced data, it will be dropped
          otherwise it will be queued for sending.
  
          Args:
              data (bytearray, string): Unstructured data to trace to any
                  connected client.
              callback (callable): Optional callback to get notified when
                  this data is actually sent.