code: def invoke_hook_bolt_ack(self, heron_tuple, process_latency_ns):
      
      if len(self.task_hooks) > 0:
        bolt_ack_info = BoltAckInfo(heron_tuple=heron_tuple,
                                    acking_task_id=self.get_task_id(),
                                    process_latency_ms=process_latency_ns * system_constants.NS_TO_MS)
        for task_hook in self.task_hooks:
          task_hook.bolt_ack(bolt_ack_info)
docs: invoke task hooks for every time bolt acks a tuple
  
      :type heron_tuple: HeronTuple
      :param heron_tuple: tuple that is acked
      :type process_latency_ns: float
      :param process_latency_ns: process latency in nano seconds