<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def trace(self, data, callback=None):
 """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. """


        if self._push_channel is None:
            return

        self._push_channel.trace(data, callback=callback)