struct ResettableLazy<Value> {
    
    private var valueHolder: ValueHolder
    
    init(initializer: @escaping () -> Value) {
        valueHolder = .unset(initializer)
    }
    
    enum ValueHolder {
        case hasValue(Value, () -> Value)
        case unset(() -> Value)
    }
}



_ = ResettableLazy<String>() { "Crashes before this part runs" }

struct ResettableLazy<Value> {
    
    private var valueHolder: ValueHolder<Value>
    
    init(initializer: @escaping () -> Value) {
        valueHolder = .unset(initializer)
    }
}
    
enum ValueHolder<Value> {
    case hasValue(Value, () -> Value)
    case unset(() -> Value)
}



_ = ResettableLazy<String>() { "Runs just fine" }