Why paging 3.0 load 2 page at beginning

I'm trying to track infinite scrolling. I've implemented the tracking in pagingsource. When I open the page, paging loads 2 pages. And without even scrolling, the track request is sending. How can i stop paging from loading 2 pages ?

ExamplePagingSource: PagingSource<String, UIItem>() {

private var scrollDepth = 0

override suspend fun load(params: LoadParams<String>): LoadResult<String, UIItem> {
    val pageKey = params.key ?: ""

    return try {
        val exampleData = getExampleData()

        
        scrollDepth++
        trackScroll()
        

        LoadResult.Page(
            data = items,
            prevKey = if (isFirstPage) null else pageKey,
            nextKey = exampleData.pageKey.ifEmpty { null }
        )
    } catch (e: Exception) {
        Timber.e(e, "Error")
        LoadResult.Error(e)
    }
}

UPDATE I solved it with prefetchDistance

I solved it with prefetchDistance. If you set prefetch distance to 2. Paging library call api at second to last item. You must set in PagingConfig

Pager(
    config = PagingConfig(
        pageSize = PAGE_SIZE,
        prefetchDistance = PREFETCH_DISTANCE
    ),
    pagingSourceFactory = ::pagingSource
)