tagIsAvailable method
Whether tag is still connected and reachable.
NFCTag.isAvailable asks about this one tag, not about the field: a tag the session
has already let go of -- polling restarted, the session ended, the card lifted and put
back -- reads false even while a card is sitting on the phone. Worth a call before a
long exchange, so a tag that has drifted out of range says so here rather than halfway
through a write.
Implementation
Future<bool> tagIsAvailable(NfcTag tag) => iosApi.tagIsAvailable(tag.handle);