Copy data read from src file obj to new file in dest_path.

def _copy(src_file, dest_path):
  """Copy data read from src file obj to new file in dest_path."""
  tf.io.gfile.makedirs(os.path.dirname(dest_path))
  with tf.io.gfile.GFile(dest_path, 'wb') as dest_file:
    while True:
      data = src_file.read(io.DEFAULT_BUFFER_SIZE)
      if not data:
        break
      dest_file.write(data)