cardRead method
if connected is true then you can call card read
Implementation
@override
Future<dynamic> cardRead(
{required String amount,
required int tranType,
required String traceNo}) async {
btCtr = Completer();
methodChannel.invokeMethod(
"bluetooth.card_read",
{
"amount": amount,
"tran_type": tranType,
"trace_no": traceNo,
},
);
return await btCtr?.future;
}