Use mbsync periodically from within Emacs

sync-mail.el

(defun elan-sync-mail ()
    "Synchronize mail-accounts using mbsync."
    (interactive)
    (if (get-buffer "*mbsync*")
        (user-error "There is already a sync in progress")
      (let* ((output-buffer (get-buffer-create "*mbsync*"))
             (proc (progn
                     (async-shell-command "mbsync -q -a" output-buffer "*mbsync-error*")
                     (get-buffer-process output-buffer))))
        (when (process-live-p proc)
          (spinner-start elan-sync-mail-spinner)
          (set-process-sentinel
           proc
           (lambda (process signal)
	     (when (memq (process-status process) '(exit signal))
               (setq elan-notmuch-last-update (current-time-string))
               (kill-buffer "*mbsync*")
	       (spinner-stop elan-sync-mail-spinner)
	       (run-hooks 'elan-sync-mail-hook))))))))
(add-to-list 'display-buffer-alist '("*mbsync*" (display-buffer-no-window)))

(let ((minutes 60))
   (run-with-timer 1 (* 15 minutes) 'elan-sync-mail))