speech/cloud-client test failures

[b-loved-dreamer]

Builds
https://source.cloud.google.com/results/invocations/ee35c95b-7ef9-4c90-b5ca-b30534a5c83b/targets
https://source.cloud.google.com/results/invocations/eace6b03-019a-4f2a-9802-4e07135a922d/targets

We don't have xunit xml log file, so build cop bot didn't catch it, but it seems like Python died.
Log:

platform linux -- Python 3.7.7, pytest-6.0.1, py-1.9.0, pluggy-0.13.1 -- /workspace/speech/cloud-client/.nox/py-3-7/bin/python
cachedir: .pytest_cache
rootdir: /workspace, configfile: pytest.ini
collecting ... collected 22 items

beta_snippets_test.py::test_transcribe_file_with_enhanced_model PASSED   [  4%]
beta_snippets_test.py::test_transcribe_file_with_metadata PASSED         [  9%]
beta_snippets_test.py::test_transcribe_file_with_auto_punctuation PASSED [ 13%]
beta_snippets_test.py::test_transcribe_diarization PASSED                [ 18%]
beta_snippets_test.py::test_transcribe_multichannel_file E0828 10:27:18.708634490   13111 sync_posix.cc:67]           assertion failed: pthread_mutex_lock(mu) == 0
Fatal Python error: Aborted

Thread 0x00007f2c36e0e600 (most recent call first):
  File "/usr/local/lib/python3.7/codecs.py", line 322 in decode
  File "/workspace/speech/cloud-client/.nox/py-3-7/lib/python3.7/site-packages/_pytest/capture.py", line 484 in snap
  File "/workspace/speech/cloud-client/.nox/py-3-7/lib/python3.7/site-packages/_pytest/capture.py", line 570 in readouterr
  File "/workspace/speech/cloud-client/.nox/py-3-7/lib/python3.7/site-packages/_pytest/capture.py", line 657 in read_global_capture
  File "/workspace/speech/cloud-client/.nox/py-3-7/lib/python3.7/site-packages/_pytest/capture.py", line 718 in item_capture
nox > Command pytest --junitxm```

[b-loved-dreamer]

Hi @tmatsuo, I ran the failing tests again with @flaky(max_runs=1000, min_passes=500) and all 4 of them passed. I submitted a PR #78 that includes changes to the samples with migrated code and passing tests.

[b-loved-dreamer]

Closing this issue.