docs: @Override
      public InitiateMultipartUploadResult initiateMultipartUpload(
              InitiateMultipartUploadRequest req) {
          boolean isCreateEncryptionMaterial = true;
          if (req instanceof EncryptedInitiateMultipartUploadRequest) {
              EncryptedInitiateMultipartUploadRequest cryptoReq = 
                      (EncryptedInitiateMultipartUploadRequest) req;
              isCreateEncryptionMaterial = cryptoReq.isCreateEncryptionMaterial();
          }
          return isCreateEncryptionMaterial
               ? crypto.initiateMultipartUploadSecurely(req)
               : super.initiateMultipartUpload(req)
               ;
      }