Fast fetch and two-way tag synchronization between notmuch and GMail

 This program can pull email and labels (and changes to labels) from your
 GMail account and store them locally in a maildir with the labels synchronized
 with a notmuch database. The changes to tags in the notmuch database may be
 pushed back remotely to your GMail account.
 .
 It will not and can not:
 * Add or delete messages on your remote account
 * Modify messages other than their labels