code: private HttpExecutor createHttpExecutor(RequestMethodHolder requestMethodHolder) {
      HttpExecutor executor;
      if (customHttpClient == null) {
        executor = executorFactory.getHttpExecutor(requestMethodHolder.getBodyType());
      } else {
        executor = executorFactory.getHttpExecutor(requestMethodHolder.getBodyType(), customHttpClient);
      }
      executor.setCharset(charset);
      executor.setProxy(this.proxy);
      executor.setTimeout(timeout.socketTimeout, timeout.connectTimeout);
      return executor;
    }
docs: 创建http executor，并设置基本属性