immutableMapTo

fun <T, R> Collection<T>.immutableMapTo(map: (T) -> R): PersistentList<R>

Maps this collection with map directly into a kotlinx.collections.immutable PersistentList, avoiding an intermediate mutable List — the usual way a TileHolder/ EventHolder's getTileSchema()/getEventSchema() converts its child holders (events.map { it.get() }) back into the immutable list shape a schema's own events/tiles field expects.