code: public Waiter<HeadBucketRequest> bucketExists() {
  
          return new WaiterBuilder<HeadBucketRequest, HeadBucketResult>()
              .withSdkFunction(new HeadBucketFunction(client))
              .withAcceptors(
                  new HttpSuccessStatusAcceptor<HeadBucketResult>(WaiterState.SUCCESS),
                  new HttpFailureStatusAcceptor<HeadBucketResult>(301, WaiterState.SUCCESS),
                  new HttpFailureStatusAcceptor<HeadBucketResult>(403, WaiterState.SUCCESS),
                  new HttpFailureStatusAcceptor<HeadBucketResult>(404, WaiterState.RETRY))
              .withDefaultPollingStrategy(
                  new PollingStrategy(new MaxAttemptsRetryStrategy(20),
                                      new FixedDelayStrategy(5)))
              .withExecutorService(executorService).build();
      }
docs: Builds a BucketExists waiter by using custom parameters waiterParameters
  and other parameters defined in the waiters specification, and then polls
  until it determines whether the resource entered the desired state or
  not, where polling criteria is bound by either default polling strategy
  or custom polling strategy.