docs: def GetMetricMetadata():
    """Returns a list of MetricMetadata for communicator-related metrics."""
    return [
        stats_utils.CreateCounterMetadata("grr_client_unknown"),
        stats_utils.CreateCounterMetadata("grr_decoding_error"),
        stats_utils.CreateCounterMetadata("grr_decryption_error"),
        stats_utils.CreateCounterMetadata("grr_authenticated_messages"),
        stats_utils.CreateCounterMetadata("grr_unauthenticated_messages"),
        stats_utils.CreateCounterMetadata("grr_rsa_operations"),
        stats_utils.CreateCounterMetadata(
            "grr_encrypted_cipher_cache", fields=[("type", str)]),
    ]