Offline Editing plugin?

When I travel by ship, plane, etc. I don’t necessarily have good wifi.

It would be cool to be able to “edit offline”, meaning at least open the topics and edit them without worrying about losing data. It can be simply stored in localStorage and posted when an internet connection is resumed.

Going one step further, being able to compose and manage multiple drafts offline, so they can be posted when I am online, would be great. As it is, I would have to use some markdown editor.