docs: public static void loadFrom(ANTLRReaderStream input, Proto target) throws Exception
      {
          // Create an ExprLexer that feeds from that stream
          ProtoLexer lexer = new ProtoLexer(input);
          // Create a stream of tokens fed by the lexer
          CommonTokenStream tokens = new CommonTokenStream(lexer);
          // Create a parser that feeds off the token stream
          ProtoParser parser = new ProtoParser(tokens);
          // Begin parsing at rule parse
          parser.parse(target);
      }