private String currentGroupPath()
        {
            final StringBuilder sb = new StringBuilder();
            groupPath.forEach(
                (token) ->
                {
                    sb.append(token.name()).append('.');
                });
            return sb.toString();
        }
Encodes the state machine as a graphviz dot diagram.
@param sb the string builder to append to.
@param indent the indentation to use.
sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/common/FieldPrecedenceModel.java