code: def test_load_fileobj(self, available_backends, expected_backend):
      f = io.BytesIO()
      format = "wav"
      buffer_size = 8192
      with patch(
          "torchaudio._backend.utils.get_available_backends",
          return_value=available_backends,
      ), patch(
          f"torchaudio._backend.utils.{expected_backend.__name__}.load"
      ) as mock_load:
          get_load_func()(f, format=format, buffer_size=buffer_size)
          mock_load.assert_called_once_with(
              f, 0, -1, True, True, format, buffer_size
          )
  
file_path: audio/test/torchaudio_unittest/backend/dispatcher/dispatcher_test.py
imports: import io
  from unittest.mock import patch
  import torch
  from parameterized import parameterized
  from torchaudio._backend.utils import FFmpegBackend, get_info_func, get_load_func, get_save_func, SoundfileBackend, SoXBackend
  from torchaudio_unittest.common_utils import PytorchTestCase
label_desc: Use image node_id 4 for calling the DispatcherTest obj's underlying member method code with example usage: obj.test_load_fileobj(available_backends, expected_backend) without return types