void _sendOnMessageToBluetooth() {
   bluetooth.isConnected.then((isConnected) {
      if (isConnected) {
         bluetooth.write(“1”);
         show(‘Device Turned On’);
      }
   });
}

void _sendOffMessageToBluetooth() {
   bluetooth.isConnected.then((isConnected) {
      if (isConnected) {
         bluetooth.write(“0”);
         show(‘Device Turned Off’);
      }
   });
}