start method
Implementation
Future<void> start() async {
if (room == null) {
transactionId = client.generateUniqueTransactionId();
}
if (encryption.crossSigning.enabled &&
!(await encryption.crossSigning.isCached()) &&
!client.isUnknownSession) {
setState(KeyVerificationState.askSSSS);
_nextAction = 'request';
} else {
await sendRequest();
}
}