saveDouble method
Method for storing a Double with a defined key.
Example:
// RCache.credentials.saveDouble(2.0, key: RCacheKey("double"));
Implementation
@override
Future<void> saveDouble(double value, {required RCacheKey key}) async {
  try {
    return await methodChannel.invokeMethod(
      RCacheMethod.key.save.double,
      rArgs(type: RCacheMethod.key.credentials, key: key, value: value),
    );
  } on PlatformException catch (e) {
    return Future.error(e);
  }
}