code: def start(self):
          
          self._lock.acquire()
          try:
              if not self._thread:
                  self._thread = Thread(target=self._target)
                  self._thread.setDaemon(True)
                  self._thread.name = "elasticapm sender thread"
                  self._thread.start()
          finally:
              self._lock.release()
docs: Starts the task thread.