code: public StorageBatchResult<Boolean> delete(BlobId blob, BlobSourceOption... options) {
      StorageBatchResult<Boolean> result = new StorageBatchResult<>();
      RpcBatch.Callback<Void> callback = createDeleteCallback(result);
      Map<StorageRpc.Option, ?> optionMap = StorageImpl.optionMap(blob, options);
      batch.addDelete(blob.toPb(), callback, optionMap);
      return result;
    }
docs: Adds a request representing the "delete blob" operation to this batch. Calling {@link
  StorageBatchResult#get()} on the return value yields {@code true} upon successful deletion,
  {@code false} if the blob was not found, or throws a {@link StorageException} if the operation
  failed.