presto-resource-group-managers/src/main/java/io/prestosql/plugin/resourcegroups/SelectorSpec.java/SelectorSpec/toString
class SelectorSpec:    @Override
    public String toString()
    {
        return toStringHelper(this)
                .add("resourceGroup", group)
                .add("userRegex", userRegex)
                .add("userFlags", userRegex.map(Pattern::flags))
                .add("sourceRegex", sourceRegex)
                .add("sourceFlags", sourceRegex.map(Pattern::flags))
                .add("queryType", queryType)
                .add("clientTags", clientTags)
                .toString();
    }