fn walk_seed(
body: &Request,
) -> (BTreeSet<OwnedEventId>, VecDeque<(OwnedEventId, bool)>)Expand description
Builds the walk’s dedup set and its initial queue.
Both caller-supplied vectors are bounded here so the traversal cost stays independent of the request size. The flag marks a seed entry, which enqueues its prev_events without yielding itself.