code: public static HttpResponse request(HttpRequest request, String body, String contentType) {
          return request.contentType(contentType).body(body).contentLength(body.length()).execute();
      }
docs: 发出网络请求
  
  @param request {@link HttpRequest}
  @param body 请求正文
  @param contentType 内容类型
  
  @return {@link HttpResponse}
  
  @since 1.1.0