mail should not block the UI
we could explore deferToProcess. for everything else, deferToThread...
(from redmine: created on 2013-12-23, closed on 2014-01-09, relates #4868 (closed))
we could explore deferToProcess. for everything else, deferToThread...
(from redmine: created on 2013-12-23, closed on 2014-01-09, relates #4868 (closed))