onConnectionEstablished method
Is called after the initial connection has been established
Implementation
@override
FutureOr<void> onConnectionEstablished(
ConnectionInfo connectionInfo, String serverGreeting) {
serverInfo = SmtpServerInfo(connectionInfo.host, connectionInfo.port,
isSecure: connectionInfo.isSecure);
log('SMTP: got server greeting $serverGreeting', initial: 'A');
}