Function upload_first 

pub fn upload_first(request: &InteractiveUpload<'_>) -> Option<i32>

What: Run the step; the status to stop with when the push must not start, or nothing when it may. Why: A missing git-lfs, a plan that cannot be worked out and a failed upload each end the push before it starts.

In TS you’d write (pseudocode):

function uploadFirst(request: InteractiveUpload): number | undefined;