Kotlin Extensions to convert Firebase Database Ref or Query to Deferred that you can 'await' on

FBExtensions.kt

fun DatabaseReference.toDeffered(): Deferred<DataSnapshot> {
    val deferred = CompletableDeferred<DataSnapshot>()

    deferred.invokeOnCompletion {
        if (deferred.isCancelled) {
            // optional, handle coroutine cancellation however you'd like here
        }
    }

    this.addListenerForSingleValueEvent(object : ValueEventListener {
        override fun onCancelled(p0: DatabaseError) {
            deferred.completeExceptionally(p0.toException())
        }

        override fun onDataChange(p0: DataSnapshot) {
            deferred.complete(p0)
        }
    })
    return deferred
}

fun Query.toDeffered(): Deferred<DataSnapshot> {
    val deferred = CompletableDeferred<DataSnapshot>()

    deferred.invokeOnCompletion {
        if (deferred.isCancelled) {
            // optional, handle coroutine cancellation however you'd like here
        }
    }

    this.addListenerForSingleValueEvent(object : ValueEventListener {
        override fun onCancelled(p0: DatabaseError) {
            deferred.completeExceptionally(p0.toException())
        }

        override fun onDataChange(p0: DataSnapshot) {
            deferred.complete(p0)
        }
    })
    return deferred
}

Usage.kt

     val ref = FirebaseDatabase.getInstance().reference.child("users")

        withContext(Dispatchers.Main) {
            //TODO Handle Exceptions
            val dataSnapshot = ref.toDeffered().await()
        }

        //OR
        launch(Dispatchers.Main) {
            //TODO Handle Exceptions
            val dataSnapshot = ref.toDeffered().await()
        }