code: def send_message(self):
          
          start = time.time()
          message = None
          if not self.initialized:
              message = self.construct_start_message()
              self.initialized = True
          else:
              message = self.construct_end_message()
  
          self.send_UDP_message(message)
          end = time.time()
  
          return end - start
docs: Send message over UDP.
  
          If tracking is disables, the bytes_sent will always be set to -1
  
          Returns:
              (bytes_sent, time_taken)