close method
Closes this facade exactly once.
An owned facade closes its underlying AlphaXClient. A borrowed facade only stops accepting facade requests; its caller-owned client remains open. Repeated calls return the same future.
Implementation
Future<void> close() {
final existing = _closeFuture;
if (existing != null) {
return existing;
}
_closed = true;
return _closeFuture = _ownsClient ? _client.close() : Future<void>.value();
}