Indicate sync state in top bar (Android)

After creating or editing a note with sync enabled, one must wait for the sync process to complete. This requires several taps to open the side menu and verify that syncing is complete.

Having an icon in the top bar to indicate sync status would save a lot of taps. Ideally, if the icon were persistent it could trigger a sync. But even if the icon is only visible while a sync is in progress, that would be a UX win.