How to convert vararg to list?

The vararg param needs to be spread with the spread * operator.

fun insertMissingEntities(vararg entities: Entity) {
  val list = listOf(*entities)
  passMissingEntities(list)
}

You can use the extension function .asList(), which does no added copying (unlike listOf with the spread operator).

fun insertMissingEntities(vararg entities: Entity) {
  passMissingEntities(entities.asList())
}