code: public CloudFile getFileReference(final String fileName) throws URISyntaxException, StorageException {
          Utility.assertNotNullOrEmpty("fileName", fileName);
  
          StorageUri subdirectoryUri = PathUtility.appendPathToUri(this.storageUri, fileName);
          return new CloudFile(subdirectoryUri, fileName, this.getShare());
      }
docs: Returns a reference to a {@link CloudFile} object that represents a file in this directory.
  
  @param fileName
  A <code>String</code> that represents the name of the file.
  
  @return A {@link CloudFile} object that represents a reference to the specified file.
  
  @throws StorageException
  If a storage service error occurred.
  @throws URISyntaxException
  If the resource URI is invalid.