docs: private HttpResponse forceSync() {
  		// 非同步状态转为同步状态
  		try {
  			this.readBody(this.in);
  		} catch (IORuntimeException e) {
  			if (e.getCause() instanceof FileNotFoundException) {
  				// 服务器无返回内容，忽略之
  			} else {
  				throw new HttpException(e);
  			}
  		} finally {
  			if (this.isAsync) {
  				this.isAsync = false;
  			}
  			this.close();
  		}
  		return this;
  	}