Deferred<YourObject>

deferred.await()

this.deferred = CompletableDeferred<YourObject>()

this.deferred.complete(yourObject)

// LIBRARY CODE

class LibInitResult

abstract class LibClass {
    
    fun initialize() {
        val initResult = LibInitResult()
        onInitialized(initResult)
    }
    
    abstract fun onInitialized(result: LibInitResult)
}

// WRAPPER

class WrapperClass(private val libInitResult: LibInitResult) {
    // expose non-suspending functions using the libInitResult
}

suspend fun buildInitializedWrapper(): WrapperClass = 
    suspendCoroutine { cont ->
        val initializer = object : LibClass() {
            override fun onInitialized(result: LibInitResult) {  
                cont.resume(WrapperClass(result))
            }
        }
        initializer.initialize()
    }