DerivedStateOfUnderTheHood.kt

fun <T> derivedStateOf(calculation: () -> T): State<T> = DerivedSnapshotState(calculation) 

//// 
private class DerivedSnapshotState<T>(
    private val calculation: () -> T
) : StateObject, DerivedState<T> {
    private var first: ResultRecord<T> = ResultRecord()

    /// class implementation
    
}

// DerivedState<T> interface
internal interface DerivedState<T> : State<T> {
    /**
     * The value of the derived state retrieved without triggering a notification to read observers.
     */
    val currentValue: T

    /**
     * A list of the dependencies used to produce [value] or [currentValue].
     *
     * The [dependencies] list can be used to determine when a [StateObject] appears in the apply
     * observer set, if the state could affect value of this derived state.
     */
    val dependencies: Set<StateObject>
}