docs: public DeleteMessageBatchResult withSuccessful(DeleteMessageBatchResultEntry... successful) {
          if (this.successful == null) {
              setSuccessful(new com.amazonaws.internal.SdkInternalList<DeleteMessageBatchResultEntry>(successful.length));
          }
          for (DeleteMessageBatchResultEntry ele : successful) {
              this.successful.add(ele);
          }
          return this;
      }