Method delta_edge

crates/kernel/src/profile.rs:399–405

Record that `consumer` delta-unfolds the body of `producer`. Self-edges are ignored. Ensures both endpoints exist as blocks (with zeroed stats if not yet seen) so the graph is well-formed even if a producer is only ever referenced, never directly checked.

(&mut self, consumer: Address, producer: Address)

/// Phase A (the kernel recorder) feeds this with one `block(..)` per checked
/// block and one `delta_edge(consumer, producer)` per recorded cross-block
/// unfold. The builder is the merge point for per-worker accumulators: calling
/// `block`/`delta_edge` is commutative and idempotent w.r.t. edge sets, so
/// merge order does not affect the result.
#[derive(Default)]
pub struct ProfileBuilder {
  blocks: FxHashMap<Address, Accum>,
}

#[derive(Default)]
struct Accum {