docs: public static <T> void mergeFrom(JsonParser parser, T message, Schema<T> schema,
              boolean numeric) throws IOException
      {
          if (parser.nextToken() != JsonToken.START_OBJECT)
          {
              throw new JsonInputException("Expected token: { but was " +
                      parser.getCurrentToken() + " on message " +
                      schema.messageFullName());
          }
  
          schema.mergeFrom(new JsonInput(parser, numeric), message);
  
          if (parser.getCurrentToken() != JsonToken.END_OBJECT)
          {
              throw new JsonInputException("Expected token: } but was " +
                      parser.getCurrentToken() + " on message " +
                      schema.messageFullName());
          }
      }