code: protected CBConnection resetSomeState() {
          url = null;
          followRedirects = CBDefaultConfig.FOLLOW_REDIRECTS;
          header.clear();
          data = null;
          if (!keepMethod) {
              method = CBDefaultConfig.METHOD;
          }
          if (!keepCharset) {
              charset = CBDefaultConfig.CHARSET;
          }
          return this;
      }
docs: 参数重置
  其中timeout,cookie,keepSession不进行重置
  
  @return 连接