Function stat_scan 

pub fn stat_scan(
    root_str: &str,
    prev_manifest: &[(String, FileState)],
    content_confirm_all: bool,
    recursive: bool,
) -> (Vec<(String, FileState)>, BTreeSet<String>)

Diff the corpus against prev_manifest by stat, content-confirming changes. Returns the rebuilt manifest (scan order) and the changed set.