LeftRightFeedbacksCombine.swift

func leftEffect(inputLevels: Levels) -> AnyPublisher<Event, Never> {
    // this is the stop condition to our Spin
    guard inputLevels.left != inputLevels.right else { return Empty().eraseToAnyPublisher() }

    // this is the regulation for the left level
    if inputLevels.left < inputLevels.right {
        return Just(.increaseLeft).eraseToAnyPublisher()
    }  else {
        return Just(.decreaseLeft).eraseToAnyPublisher()
    }
}

func rightEffect(inputLevels: Levels) -> AnyPublisher<Event, Never> {
    // this is the stop condition to our Spin
    guard inputLevels.left != inputLevels.right else { return Empty().eraseToAnyPublisher() }

    // this is the regulation for the right level
    if inputLevels.right < inputLevels.left {
        return Just(.increaseRight).eraseToAnyPublisher()
    }  else {
        return Just(.decreaseRight).eraseToAnyPublisher()
    }
}