docs: static Promise<Boolean> toBooleanPromise(Future<?> future) {
  
          DefaultPromise<Boolean> result = new DefaultPromise<>(GlobalEventExecutor.INSTANCE);
  
          if (future.isDone() || future.isCancelled()) {
              if (future.isSuccess()) {
                  result.setSuccess(true);
              } else {
                  result.setFailure(future.cause());
              }
              return result;
          }
  
          future.addListener((GenericFutureListener<Future<Object>>) f -> {
  
              if (f.isSuccess()) {
                  result.setSuccess(true);
              } else {
                  result.setFailure(f.cause());
              }
          });
          return result;
      }