옵트인(Opt-in)

 특정 기능이나 API를 사용할 때, 사용자가 이를 명시적으로 허용해야 한다는 개념

주로 실험적(Experimental) 기능이나 제한적인 API에 적용

해당 기능이 아직 안정적이지 않거나, 향후 변경 가능성이 있다는 점을 인지

 

@RequiresOptIn(level = RequiresOptIn.Level.WARNING)
annotation class ExperimentalFeature

@ExperimentalFeature
fun experimentalFunction() {
    println("This is an experimental feature.")
}

@OptIn(ExperimentalFeature::class)
fun main() {
    experimentalFunction() // 명시적으로 옵트인해야 실행 가능
}