Even the email based flow presents a series of changes as a thread of email messages, so the association between changes that are related or depend on each othe

Even the email based flow presents a series of changes as a thread of email messages, so the association between changes that are related or depend on each other is maintained. Once a patch set looks good to the maintainer, it's merged. Email clients do enforce looking at the changes as a series of diffs on a per commit basis.