fn node_identity(req: &HeartbeatRequest) -> Option<u64>Expand description
Extracts the flownode identity from a heartbeat request.
Prefers header.member_id — the canonical identity metasrv uses for
flownodes (see get_node_id in src/meta-srv/src/service/heartbeat.rs).
Falls back to peer.id, the operator-configured node id, which is also
unique within the cluster (a flownode requires node_id in its config, see
src/cmd/src/flownode.rs). Returns None when neither is present.