docs: public boolean doesBucketExist(DoesBucketExistRequest request) {
          checkNotNull(request, "request should not be null.");
          try {
              this.invokeHttpClient(this.createRequest(request, HttpMethodName.HEAD), BosResponse.class);
              return true;
          } catch (BceServiceException e) {
              // Forbidden means that the bucket exists.
              if (e.getStatusCode() == StatusCodes.FORBIDDEN) {
                  return true;
              }
              if (e.getStatusCode() == StatusCodes.NOT_FOUND) {
                  return false;
              }
              throw e;
          }
      }