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Description
Related to PR #583, it is not supported to use attempt_direct_path and ssl_credentials because we use grpc.compute_engine_channel_credentials for Direct Path which doesn't support passing ssl_credentials. Support for mTLS and Direct Path will be added later.
See the comment below
# if `ssl_credentials` is set, use `grpc.composite_channel_credentials` instead of
# `grpc.compute_engine_channel_credentials` as the former supports passing
# `ssl_credentials` via `channel_credentials` which is needed for mTLS.