BlockBlobAsyncClient getBlockBlobAsyncClient(String containerName, String blobName, boolean autoCreateContainer) {
    BlobContainerAsyncClient containerAsyncClient = getAsyncContainerClient(containerName, autoCreateContainer);
    return containerAsyncClient.getBlobAsyncClient(blobName).getBlockBlobAsyncClient();
  }
Get the block blob async client for the supplied Azure container and blob name.
@param containerName name of the Azure container where the blob lives.
@param blobName name of the blob.
@param autoCreateContainer flag indicating whether to create the container if it does not exist.
@return {@code BlockBlobClient} reference.
ambry-cloud/src/main/java/com/github/ambry/cloud/azure/StorageClient.java