IssueTracker

I have an Adapter which extends ListAdapter<DataItem> with DiffUtils. Lets I have following sealed class to submit item in Adapter :

sealed class DataItem {

    abstract val id

    data class Header(var item: T)) {
        ovveride val id = 1
    } :  : DataItem()

    data class Product(var item : R) {
       ovveride val id =2
   } : DataItem()
}

When all of items are the same for instance from Product type, adapter.currentList is the size as expected :

adapter.submitList(products)
Log.d(TAG, adapter.currentList.size.toString())     // Result is 33

It prints size of products which are submitted. For instance 33.

Now imagine first I submit a header in onCreateView of Fragment :

adapter.submitList(header)
Log.d(TAG, adapter.currentList.size.toString()).  //Result is 1

And then from a api response I submit my products

adapter.submitList(header + products)

Now the current list of Adapter is just one ( adapter.currentList.size = 1). Seems that submitList works async

Then if I add a delay it works as expected and size is 34 :

CoroutineScope(Dispatchers.Main).launch {
      adapter.submitList(header + products)
     delay(2000)
    Log.d(TAG, adapter.currentList.size.toString()). //Result is 34
}

Why submitList is async in this case when we have a different header and not all item the same?