@Override
  public CompletableFuture<Boolean> deleteFile(String containerName, String fileName) throws BlobStorageException {
    // TODO call getAzureStorageClient() once blobId is passed down to this routine.
    return getMetadataAzureStorageClient().deleteFile(containerName, fileName);
  }
Delete a file from blob storage asynchronously, if it exists.
@param containerName name of the container containing file to delete.
@param fileName name of the file to delete.
@return a {@link CompletableFuture} of type {@link Boolean} that will eventually complete successfully when the file
        is deleted or will complete exceptionally if an error occurs.
ambry-cloud/src/main/java/com/github/ambry/cloud/azure/ShardedStorageClient.java