Bug: SetScanPeriod and SetBetweenScanPeriod Methods Missing Return Statements Leading to IllegalStateException

[ktanaka101]

Summary:

In the FlutterBeaconPlugin, the setScanPeriod and setBetweenScanPeriod method handlers within the onMethodCall function do not include return statements after invoking result.success or result.error.

This omission causes the method to continue execution and inadvertently call result.notImplemented(),
resulting in an IllegalStateException due to multiple responses being sent for a single method call.

Steps to Reproduce:

1. Invoke the setScanPeriod method from the Flutter side with a valid scanPeriod argument.
2. Observe that after successfully setting the scan period, an IllegalStateException is thrown.
   Log: java.lang.IllegalStateException: Reply already submitted

[dariocavada]

Try the updated version of this library, now ported to Kotlin with support for Flutter 3.x, Gradle, and an improved example:
https://pub.dev/packages/dchs_flutter_beacon