code: public FluentValidator putClosure2Context(String key, Closure value) {
          if (context == null) {
              context = new ValidatorContext();
          }
          context.setClosure(key, value);
          return this;
      }
docs: 将闭包注入上下文
  
  @param key   键
  @param value 闭包
  
  @return FluentValidator