Example delegation pattern for Kotlin data classes

Device.kt

sealed interface Device {
    val metadata: Metadata

    data class Camera(
        override val metadata: Metadata,
        val extras: Map<Int, String>
    ) : Device

    data class Thermostat(
        override val metadata: Metadata
    ) : Device

    data class DoorLock(
        override val metadata: Metadata
    ) : Device

    sealed interface Metadata {
        val id: String
        val name: String

        data class Summary(
            override val id: String,
            override val name: String
        ) : Metadata

        data class Detail(
            val summary: Summary,
            val description: String,
            val notes: String
        ) : Metadata by summary
    }
}