docs: def CreateCounterMetadata(metric_name, fields=None, docstring=None, units=None):
    """Helper function for creating MetricMetadata for counter metrics."""
    return rdf_stats.MetricMetadata(
        varname=metric_name,
        metric_type=rdf_stats.MetricMetadata.MetricType.COUNTER,
        value_type=rdf_stats.MetricMetadata.ValueType.INT,
        fields_defs=FieldDefinitionProtosFromTuples(fields or []),
        docstring=docstring,
        units=units)