docs: public static synchronized void shootBowgunEmptyScheduling() { // called by e.g. UTFlute
          assertUnlocked();
          if (bowgunEmptyScheduling) { // already empty
              return;
          }
          if (logger.isInfoEnabled()) {
              logger.info("...Shooting bowgun empty scheduling: true");
          }
          bowgunEmptyScheduling = true; // should be before container initialization
          lock(); // auto-lock here, because of deep world
      }