how to employ androidx.paging.RemoteMediator to load more data when user scrolls to bottom of list

Question

I am building a hobby android application to investigate jetpack compose and large lists. I am using the Marvel Comics rest api that has over 30,000 comics to display. this api implements paging using a limit 100 items or less each call and an offset to allow calls to retrieve 100 (or less) items each call.

i wanted to try developing a custom RemoteMediator with the room paging library, however it is not working as i expected.

I thought my lazy list would be populated with the first "N" comics retrieved from the api then no more api calls would be triggered until the user had scrolled to the bottom of my list.

My compose component collects the comics list as follows: -

 val viewModel: ComicViewModel = hiltViewModel()
 val comics = viewModel.comics.collectAsLazyPagingItems()

Scaffold(
    topBar = { ComicsTopAppBar(onNavigateBack = onNavigateBack) }
) { innerPadding ->
    Box(
        modifier = Modifier
            .fillMaxSize()
            .padding(innerPadding)
    ) {
        if (comics.loadState.refresh is LoadState.Loading) {
            CircularProgressIndicator(
                modifier = Modifier.align(Alignment.Center)
            )
        } else {
            LazyColumn(
                modifier = Modifier.fillMaxSize(),
                verticalArrangement = Arrangement.spacedBy(16.dp),
                horizontalAlignment = Alignment.CenterHorizontally
            ) {
                items(
                    count = comics.itemCount,
                    key = comics.itemKey { it.id },
                    contentType = comics.itemContentType { "MyPagingItems" }
                ) { index ->
                    val item = comics[index]
                    ComicItem(comic = item!!)
                }
                item {
                    if (comics.loadState.append is LoadState.Loading) {
                        CircularProgressIndicator()
                    }
                }
            }
        }
    }
}

I then expected the next api call to be made to retrieve the second "page" of data.

What is actually happening is that api calls are made continuously.

my custom RemoteMediator resembles this: -

import android.util.Log
import androidx.paging.ExperimentalPagingApi
import androidx.paging.LoadType
import androidx.paging.PagingState
import androidx.paging.RemoteMediator
import org.research.development.marvel.common.model.database.ComicDO
import org.research.development.marvel.viewmodel.ComicRepository

private const val TAG = "ComicRemoteMediator"

@OptIn(ExperimentalPagingApi::class)
class ComicRemoteMediator(private val repository: ComicRepository) : RemoteMediator<Int, ComicDO>() {

    override suspend fun load(loadType: LoadType, state: PagingState<Int, ComicDO>): MediatorResult {
        Log.d(TAG, "load() called with: loadType = $loadType")

        return try {

            when (loadType) {
                LoadType.REFRESH -> Unit
                LoadType.PREPEND -> return MediatorResult.Success(endOfPaginationReached = true)
                LoadType.APPEND -> Unit
            }

            val endOfPaginationReached = repository.comics(state.config.pageSize)

            MediatorResult.Success(endOfPaginationReached = endOfPaginationReached)
        } catch (e: Exception) {
            MediatorResult.Error(e)
        }
    }
}

my repository comics function resembles this: -

class ComicRepository @Inject constructor(private val service: MarvelComicsApi, val database: MarvelComicDatabase) {

    private val comicsDO = ArrayList<ComicDO>()

    suspend fun comics(pageSize: Int): Boolean {

        comicsDO.clear()

        yield()

        service.comics(queryParameters = manufactureQueryParameters(pageSize))
            .onLeft { callError -> Log.e(TAG, "comics: $callError") }
            .onRight { comicResponse ->

                comicResponse.data.results.forEach { result ->
                    comicsDO.add(
                        ComicDO(
                            id = result.id,
                            title = result.title,
                            description = result.description ?: "MISSING",
                            onSaleDate = result.dates.first { saleDate -> saleDate.type == "onsaleDate" }.date,
                            imageUrl = "${result.thumbnail.path}.${result.thumbnail.extension}"
                        )
                    )
                }

                database.comicDAO.cache(comicsDO)

                endOfPaginationReached = comicResponse.data.total == database.comicDAO.count()

            }

        comicsDO.clear()

        return endOfPaginationReached
    }

    private suspend fun manufactureQueryParameters(limit: Int, timestamp: String = System.currentTimeMillis().toString()): Map<String, String> = mapOf(
        "format" to "comic",
        "formatType" to "comic",
        "noVariants" to "true",
        "limit" to limit.toString(),
        "offset" to database.comicDAO.count().toString(),
        "ts" to timestamp,
        "hash" to messageDigest5(generateApiHash(timestamp = timestamp)).toHex(),
        "apikey" to "@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"
    )
}

This issue (I Believe) is that i set MediatorResult.Success(endOfPaginationReached = false) until the api has retrieved all the comics available.

Is my expectation of the RemoteMediator behaviour wrong?

Is it possible to get the RemoteMediator to only load subsequent "pages" of comics when the user scrolls to the bottom of the list?