@Override
  public CompletableFuture<List<Response<Void>>> deleteBatch(List<CloudBlobMetadata> batchOfBlobs) {
    // TODO call getAzureStorageClient() once blobId is passed down to this routine.
    return getMetadataAzureStorageClient().deleteBatch(batchOfBlobs);
  }
Deletes a list of blobs asynchronously.
@param batchOfBlobs {@link List} of {@link CloudBlobMetadata} objects.
@return a {@link CompletableFuture} that will eventually contain {@link List} of {@link Response}s for the blobs
        in the batch or an exception if an error occurred.
ambry-cloud/src/main/java/com/github/ambry/cloud/azure/ShardedStorageClient.java