baseUrl property
The address this service announced it is listening on, exactly as it wrote it — or null until it has announced one.
Taken from the child's own Serving at … line rather than rebuilt from
port, because that line is the only place the app prefix appears.
revali up hands out the port; it has no idea the app mounts itself under
/api, and a base missing the prefix sends every route click to a 404.
Null is meaningful and is left null on purpose: a route path clicked before its service is serving has no base, and there is nothing to guess from. Opening the wrong URL is worse than opening none.
Kept across a reload. The child re-announces when it comes back up and overwrites this; in the gap the old address is still the best answer there is, and it is nearly always still the right one — the port does not move.
Implementation
String? get baseUrl => _baseUrl;