code: func housekeepingHandler(c *router.Context) {
  	tsmon.GetState(c.Context).RunGlobalCallbacks(c.Context)
  	if err := AssignTaskNumbers(c.Context); err != nil {
  		logging.WithError(err).Errorf(c.Context, "Task number assigner failed")
  		c.Writer.WriteHeader(http.StatusInternalServerError)
  	}
  }
docs: // housekeepingHandler performs task number assignments and runs global metric
  // callbacks.
  //
  // See DatastoreTaskNumAllocator and AssignTaskNumbers.