本地测试 ELPA 镜像的速度

Emacs-general
9

新增了一个 sjtu 的镜像，写了更简单的代码测试下：

;; `seq-sort-by', added at Emacs 26.1
(require 'seq)

(defun find-fastest-mirror-for-me ()
  (interactive)
  (pp
   (seq-sort-by
    #'cdr
    #'<
    (mapcar
     (lambda (pair)
       (let ((name (car pair))
             (url  (cdr pair)))
         (cons
          name
          (benchmark-elapse
            (url-copy-file
             (concat url "archive-contents")
             null-device
             'OK-IF-ALREADY-EXISTS)))))
     '((163         . "https://mirrors.163.com/elpa/melpa/")
       (emacs-china . "https://elpa.emacs-china.org/melpa/")
       (sjtu        . "https://mirrors.sjtug.sjtu.edu.cn/emacs-elpa/melpa/")
       (tencent     . "https://mirrors.cloud.tencent.com/elpa/melpa/")
       (tuna        . "https://mirrors.tuna.tsinghua.edu.cn/elpa/melpa/"))))))

我这的结果，单位是秒，除了 Emacs China 其它都很快，请求的是 MELPA 的 archive-contents，大小 1575961 bytes（1.5 MB）

((sjtu . 0.394764)
 (163 . 0.458133)
 (tuna . 0.610646)
 (tencent . 0.906701)
 (emacs-china . 11.395072))