The IMAP worker has a few methods that post a new Action to itself. This
can create a deadlock when the worker.Actions channel is full: The
worker can't accept a new Action because it's trying to post an action.
This is most noticeable when cached headers are enabled and the message
list is scrolled fast.
Use a goroutine to post actions to the worker when posting from within
the worker.
Fixes: https://todo.sr.ht/~rjarry/aerc/45
Fixes: 7aa71d334b ("imap: add option to cache headers")
Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Robin Jarry <robin@jarry.cc>
f4d6ade429