closed method
returns true if sockets are closed/null wait 30 seconds to ensure network has a chance
Implementation
Future<bool> closed() async {
bool closed = false;
await Future.delayed(Duration(seconds: 30));
if ((_connectionsA == 0) || (_connectionsB == 0)) {
_socketA?.destroy();
_socketB?.destroy();
// Some time for the IP stack to destroy
await Future.delayed(Duration(seconds: 3));
}
if ((_socketA == null) || (_socketB == null)) {
closed = true;
}
return (closed);
}