abstract class MeteringCommunicationState {
  const MeteringCommunicationState();
}

class InitState extends MeteringCommunicationState {
  const InitState();
}

abstract class SourceState extends MeteringCommunicationState {
  const SourceState();
}

abstract class ScreenState extends MeteringCommunicationState {
  const ScreenState();
}

class MeasureState extends SourceState {
  const MeasureState();
}

class MeasuredState extends ScreenState {
  final double ev100;

  const MeasuredState(this.ev100);
}