code: public RouteMethod param(String name, Consumer<RouteParameter> customizer) {
      parameters().stream()
          .filter(p -> name.equals(p.name()))
          .findFirst()
          .ifPresent(customizer);
      return this;
    }
docs: Find a parameter by name and invoke the given callback.
  
  @param name Parameter name.
  @param customizer Success callback.
  @return This method.