install static method
Begin failing every non-whitelisted outbound socket attempt with
NetworkIsolationViolation. whitelist lanes (FR-006) are
permitted and logged as approved exceptions; the empty whitelist —
the default — blocks every socket (safest default, unchanged #832
behavior). Calling install while already active is a no-op, so
test setUpAll hooks can call it unconditionally.
Implementation
static void install({List<SocketLane> whitelist = const []}) {
if (_active) return;
_lanes = List.of(whitelist);
_approved.clear();
_savedIO = IOOverrides.current;
_savedHttp = HttpOverrides.current;
IOOverrides.global = _GuardedIOOverrides();
HttpOverrides.global = _GuardedHttpOverrides();
_active = true;
}