(let ((src-folder (elmo-pipe-folder-src-internal folder))
(dst-folder (elmo-pipe-folder-dst-internal folder)))
(when (and (elmo-folder-plugged-p src-folder)
(let ((src-folder (elmo-pipe-folder-src-internal folder))
(dst-folder (elmo-pipe-folder-dst-internal folder)))
(when (and (elmo-folder-plugged-p src-folder)