heartbeatEnabled

Consumer opt-in for the location-tracking heartbeat. Defaults to disabled — the SDK never sends a live location signal unless the host explicitly enables it here.

This is the supported replacement for the deprecated AFCore.setHeartbeatEnabled. When left unset, the SDK preserves whatever per-install choice was already persisted (including one made via the legacy setter), so existing integrations keep working unchanged.

The opt-in survives logout (it's per-install, not per-session) and is cleared only by an encrypted-prefs reset / Keychain wipe.