I've started work on a large, open-source project recently. This project uses a mailing list for development, thus all patches must be mailed to this mailing list. This marks a change from my previous work where I used Gerrit or GitHub pull requests.
One of the biggest issues I'm finding is how to collaborate on these patches. I have my local copy of the upstream repo, which I work on, but there isn't a "shared repo". This means I can't work on a features with teammates via feature branches or Gerrit topics (my previous workflow). The best I can do is submit patches back and forth via email, which is painful.
Given the prevalence of projects using this style of development, I imagine it's a "solved" problem. As such, could anyone recommend a general practice to follow for this kind of development?