close method
Closes all open databases (keeping their keys) and stops the transport.
Use forget to additionally delete a database's key from the KeyStore.
Implementation
Future<void> close() async {
_pairing?.disarm();
for (final db in _databases.values) {
await db.close();
}
_databases.clear();
_databaseKeys.clear();
await _transport.stop();
await _events.close();
}