Connect to start background cillecting

[huanggui924]

I/BluetoothSocket( 9163): BT connect calling pid/uid = 9163/10740, pkgName=io.github.edufolly.flutterbluetoothserialexample
I/flutter ( 9163): PlatformException(connect_error, read failed, socket might closed or timeout, read ret: -1, java.io.IOException: read failed, socket might closed or timeout, read ret: -1
I/flutter ( 9163): at android.bluetooth.BluetoothSocket.readAll(BluetoothSocket.java:838)
I/flutter ( 9163): at android.bluetooth.BluetoothSocket.readInt(BluetoothSocket.java:852)
I/flutter ( 9163): at android.bluetooth.BluetoothSocket.connect(BluetoothSocket.java:443)
I/flutter ( 9163): at io.github.edufolly.flutterbluetoothserial.BluetoothConnection.connect(BluetoothConnection.java:57)
I/flutter ( 9163): at io.github.edufolly.flutterbluetoothserial.BluetoothConnection.connect(BluetoothConnection.java:64)
I/flutter ( 9163): at io.github.edufolly.flutterbluetoothserial.FlutterBluetoothSerialPlugin$FlutterBluetoothSerialMethodCallHandler.lambda$onMethodCall$4$FlutterBluetoothSerialPlugin$FlutterBluetoothSerialMethodCallHandler(FlutterBluetoothSerialPlugin.java:1007)
I/flutter ( 9163): at io.github.edufolly.flutterbluetoothserial.-$$Lambda$FlutterBluetoothSerialPlugin$FlutterBluetoothSerialMethodCallHandler$DZLg1SWj2Aas0tcY7uTlx8xsy4Y.run(Unknown Source:10)
I/flutter ( 9163): at andr