Function tree_diff_stat_parallel 

pub fn tree_diff_stat_parallel(
    odb: &Odb,
    entries: Vec<DiffEntry>,
    config: &ConfigSet,
    thread_policy: &ThreadPolicy,
    diff_options: DiffOptions,
) -> Result<Vec<(DiffEntry, bool, Option<LineStat>)>>

Per-file line counts for stat modes (loads blobs, no hunk allocation).

Worker threads are used only for 16 or more entries (or the policy’s ThreadPolicy::min_items_override); smaller diffs run on the calling thread.

Errors

Propagates object database read failures.