code: static Action0 startCurrentThreadExecutingCommand(HystrixCommandKey key) {
          final ConcurrentStack<HystrixCommandKey> list = currentCommand.get();
          try {
              list.push(key);
          } catch (Exception e) {
              logger.warn("Unable to record command starting", e);
          }
          return new Action0() {
  
              @Override
              public void call() {
                  endCurrentThreadExecutingCommand(list);
              }
  
          };
      }
docs: /* package