kill buffer created by url-retrieve-synchronously

[Peter Münster]

Hi,

A timer calls periodically this function:

--8<---------------cut here---------------start------------->8---
(defun pm/get-json (url)
  "Copied from
http://frozenlock.org/2012/07/07/url-retrieve-and-json-api/.";
  (let* ((url-mime-encoding-string "identity")
         (buffer (with-timeout (3 nil) (url-retrieve-synchronously url)))
         (result 
          (with-current-buffer buffer
            (goto-char (point-min))
            (re-search-forward "^$")
            (json-read))))
    (kill-buffer buffer)
    result))
--8<---------------cut here---------------end--------------->8---

Sometimes, the buffers created by url-retrieve-synchronously are not
killed, because I see them in (buffer-list).

What should I do to ensure, that these buffers are always killed at the
end of the function please?

TIA for any help,
-- 
           Peter