Function push_force_with_lease 

pub fn push_force_with_lease(
    remote: &str,
    branches: &[String],
) -> Result<Vec<String>>

Force-push branches (with lease), returning the branches that actually landed. Normally that is all of them; the exception is the merge-queue backstop below, which drops a held-back branch from the returned set so the caller never reports a branch as both held and pushed.