send method
sends a ClientMsg to relay transport sink, throw an error if relay not connected
Implementation
void send(RelayConnectivity relayConnectivity, ClientMsg msg) async {
if (relayConnectivity.relayTransport == null) {
throw Exception("relay not connected");
}
/// wait until rdy
await relayConnectivity.relayTransport!.ready;
final String encodedMsg = jsonEncode(msg.toJson());
_sendRaw(relayConnectivity, encodedMsg);
}