androidx.paging

fun Config(
    pageSize: Int,
    prefetchDistance: Int = pageSize,
    enablePlaceholders: Boolean = true,
    initialLoadSizeHint: Int = pageSize * PagedList.Config.Builder.DEFAULT_INITIAL_PAGE_MULTIPLIER,
    maxSize: Int = PagedList.Config.MAX_SIZE_UNBOUNDED
): PagedList.Config

Constructs a PagedList.Config, convenience for PagedList.Config.Builder.

fun <Key : Any, Value : Any> PagedList(
    dataSource: DataSource<Key, Value>,
    config: PagedList.Config,
    notifyExecutor: Executor,
    fetchExecutor: Executor,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    initialKey: Key? = null
): PagedList<Value>

Constructs a PagedList, convenience for PagedList.Builder.

suspend fun Flow<CombinedLoadStates>.awaitNotLoading(): CombinedLoadStates?

Function to wait on a Flow until a load has completed.

It collects on the Flow and suspends until it collects and returns the firstOrNull CombinedLoadStates where all LoadStates have settled into a non-loading state i.e. LoadState.NotLoading or LoadState.Error.

A use case could be scrolling to a position after refresh has completed:

override fun onCreate(savedInstanceState: Bundle?) {
    ...
    refreshButton.setOnClickListener {
        pagingAdapter.refresh()
        lifecycleScope.launch {
            // wait for refresh to complete
            pagingAdapter.loadStateFlow.awaitNotLoading()
            // do work after refresh
            recyclerView.scrollToPosition(position)
        }
   }
}

fun <T : Any> LiveData<PagingData<T>>.cachedIn(lifecycle: Lifecycle): LiveData<PagingData<T>>

Operator which caches a LiveData of PagingData within the scope of a Lifecycle.

cachedIn multicasts pages loaded and transformed by a PagingData, allowing multiple observers on the same instance of PagingData to receive the same events, avoiding redundant work, but comes at the cost of buffering those pages in memory.

Calling cachedIn is required to allow calling androidx.paging.AsyncPagingDataAdapter on the same instance of PagingData emitted by Pager or any of its transformed derivatives, as reloading data from scratch on the same generation of PagingData is an unsupported operation.

fun <T : Any> Flow<PagingData<T>>.cachedIn(scope: CoroutineScope): Flow<PagingData<T>>

Caches the PagingData such that any downstream collection from this flow will share the same PagingData.

The flow is kept active as long as the given scope is active. To avoid leaks, make sure to use a scope that is already managed (like a ViewModel scope) or manually cancel it when you don't need paging anymore.

A common use case for this caching is to cache PagingData in a ViewModel. This can ensure that, upon configuration change (e.g. rotation), then new Activity will receive the existing data immediately rather than fetching it from scratch.

Calling cachedIn is required to allow calling androidx.paging.AsyncPagingDataAdapter on the same instance of PagingData emitted by Pager or any of its transformed derivatives, as reloading data from scratch on the same generation of PagingData is an unsupported operation.

Note that this does not turn the Flow<PagingData> into a hot stream. It won't execute any unnecessary code unless it is being collected.

import androidx.activity.viewModels
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.ViewModel
import androidx.lifecycle.lifecycleScope
import androidx.lifecycle.viewModelScope
import androidx.paging.Pager
import androidx.paging.PagingConfig
import androidx.paging.cachedIn
import androidx.paging.map

class MyViewModel : ViewModel() {
    val flow = Pager(
        config = PagingConfig(pageSize = 40),
        pagingSourceFactory = pagingSourceFactory
    ).flow
        // Loads and transformations before the cachedIn operation will be cached, so that
        // multiple observers get the same data. This is true either for simultaneous
        // observers, or e.g. an Activity re-subscribing after being recreated
        .cachedIn(viewModelScope)
}

class MyActivity : AppCompatActivity() {
    val pagingAdapter = MyPagingAdapter()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val viewModel by viewModels<MyViewModel>()

        lifecycleScope.launch {
            viewModel.flow
                // Any transformations after the ViewModel's cachedIn step will not be cached,
                // and will instead by re-run immediately on Activity re-creation.
                .map { pagingData ->
                    // example un-cached transformation
                    pagingData.map { UiModel(it) }
                }
                .collectLatest {
                    pagingAdapter.submitData(it)
                }
        }
    }
}

fun <T : Any> LiveData<PagingData<T>>.cachedIn(scope: CoroutineScope): LiveData<PagingData<T>>

Operator which caches a LiveData of PagingData within a CoroutineScope.

cachedIn multicasts pages loaded and transformed by a PagingData, allowing multiple observers on the same instance of PagingData to receive the same events, avoiding redundant work, but comes at the cost of buffering those pages in memory.

Calling cachedIn is required to allow calling androidx.paging.AsyncPagingDataAdapter on the same instance of PagingData emitted by Pager or any of its transformed derivatives, as reloading data from scratch on the same generation of PagingData is an unsupported operation.

fun <T : Any> LiveData<PagingData<T>>.cachedIn(viewModel: ViewModel): LiveData<PagingData<T>>

Operator which caches a LiveData of PagingData within the scope of a ViewModel.

cachedIn multicasts pages loaded and transformed by a PagingData, allowing multiple observers on the same instance of PagingData to receive the same events, avoiding redundant work, but comes at the cost of buffering those pages in memory.

Calling cachedIn is required to allow calling androidx.paging.AsyncPagingDataAdapter on the same instance of PagingData emitted by Pager or any of its transformed derivatives, as reloading data from scratch on the same generation of PagingData is an unsupported operation.

fun <T : Any> PagingData<T>.filter(predicate: suspend (T) -> Boolean): PagingData<T>

Returns a PagingData containing only elements matching the given predicate

fun <T : Any> PagingData<T>.filter(executor: Executor, predicate: (T) -> Boolean): PagingData<T>

Returns a PagingData containing only elements matching the given predicate.

fun <T : Any> PagingData<T>.filterAsync(
    predicate: AsyncFunction<T, Boolean>,
    executor: Executor
): PagingData<T>

Returns a PagingData containing only elements matching the given predicate.

fun <T : Any, R : Any> PagingData<T>.flatMap(transform: suspend (T) -> Iterable<R>): PagingData<R>

Returns a PagingData of all elements returned from applying the given transform to each element, as it is loaded.

fun <T : Any, R : Any> PagingData<T>.flatMap(
    executor: Executor,
    transform: (T) -> Iterable<R>
): PagingData<R>

Returns a PagingData of all elements returned from applying the given transform to each element, as it is loaded.

fun <T : Any, R : Any> PagingData<T>.flatMapAsync(
    transform: AsyncFunction<T, Iterable<R>>,
    executor: Executor
): PagingData<R>

Returns a PagingData of all elements returned from applying the given transform to each element, as it is loaded.

fun <T : Any> PagingData<T>.insertFooterItem(
    terminalSeparatorType: TerminalSeparatorType = FULLY_COMPLETE,
    item: T
): PagingData<T>

Returns a PagingData containing each original element, with the passed footer item added to the end of the list.

The footer item is added to a loaded page which marks the end of the data stream in the LoadType.APPEND direction, either by returning null in PagingSource.LoadResult.Page.nextKey. It will be removed if the last page in the list is dropped, which can happen in the case of loaded pages exceeding PagingConfig.maxSize.

Note: This operation is not idempotent, calling it multiple times will continually add more footers to the end of the list, which can be useful if multiple footer items are required.

fun <T : Any> PagingData<T>.insertHeaderItem(
    terminalSeparatorType: TerminalSeparatorType = FULLY_COMPLETE,
    item: T
): PagingData<T>

Returns a PagingData containing each original element, with the passed header item added to the start of the list.

The header item is added to a loaded page which marks the end of the data stream in the LoadType.PREPEND direction by returning null in PagingSource.LoadResult.Page.prevKey. It will be removed if the first page in the list is dropped, which can happen in the case of loaded pages exceeding PagingConfig.maxSize.

Note: This operation is not idempotent, calling it multiple times will continually add more headers to the start of the list, which can be useful if multiple header items are required.

fun <T : R, R : Any> PagingData<T>.insertSeparators(
    terminalSeparatorType: TerminalSeparatorType = FULLY_COMPLETE,
    generator: suspend (T?, T?) -> R?
): PagingData<R>

Returns a PagingData containing each original element, with an optional separator generated by generator, given the elements before and after (or null, in boundary conditions).

Note that this transform is applied asynchronously, as pages are loaded. Potential separators between pages are only computed once both pages are loaded.

import androidx.paging.insertSeparators

/*
 * Create letter separators in an alphabetically sorted list.
 *
 * For example, if the input is:
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map { pagingData ->
    // map outer stream, so we can perform transformations on each paging generation
    pagingData.insertSeparators { before: String?, after: String? ->
        if (after != null && before?.first() != after.first()) {
            // separator - after is first item that starts with its first letter
            after.first().uppercaseChar().toString()
        } else {
            // no separator - either end of list, or first letters of before/after are the same
            null
        }
    }
}

import androidx.paging.insertSeparators
import androidx.paging.map

open class UiModel
data class ItemUiModel(val item: Item) : UiModel()
data class SeparatorUiModel(val char: Char) : UiModel()

/*
 * Create letter separators in an alphabetically sorted list of Items, with UiModel objects.
 *
 * For example, if the input is (each an `Item`):
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output a list of UiModels corresponding to:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map { pagingData ->
    // map outer stream, so we can perform transformations on each paging generation
    pagingData
        .map { item ->
            ItemUiModel(item) // convert items in stream to ItemUiModel
        }
        .insertSeparators<ItemUiModel, UiModel> { before: ItemUiModel?, after: ItemUiModel? ->
            if (after != null && before?.item?.label?.first() != after.item.label.first()) {
                // separator - after is first item that starts with its first letter
                SeparatorUiModel(after.item.label.first().uppercaseChar())
            } else {
                // no separator - either end of list, or first letters of before/after are the same
                null
            }
        }
}

fun <R : Any, T : R> PagingData<T>.insertSeparators(
    terminalSeparatorType: TerminalSeparatorType = TerminalSeparatorType.FULLY_COMPLETE,
    executor: Executor,
    generator: (T?, T?) -> R?
): PagingData<R>

Returns a PagingData containing each original element, with an optional separator generated by generator, given the elements before and after (or null, in boundary conditions).

Note that this transform is applied asynchronously, as pages are loaded. Potential separators between pages are only computed once both pages are loaded.

Kotlin callers should instead use the suspending extension function variant of insertSeparators

/*
 * Create letter separators in an alphabetically sorted list.
 *
 * For example, if the input is:
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map(pagingData ->
        // map outer stream, so we can perform transformations on each paging generation
        PagingDataTransforms.insertSeparators(pagingData, bgExecutor,
                (@Nullable String before, @Nullable String after) -> {
                    if (after != null && (before == null
                            || before.charAt(0) != after.charAt(0))) {
                        // separator - after is first item that starts with its first
                        // letter
                        return Character.toString(
                                Character.toUpperCase(after.charAt(0)));
                    } else {
                        // no separator - either end of list, or first
                        // letters of items are the same
                        return null;
                    }
                }));

/*
 * Create letter separators in an alphabetically sorted list of Items, with UiModel
 * objects.
 *
 * For example, if the input is (each an `Item`):
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output a list of UiModels corresponding to:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map(itemPagingData -> {
    // map outer stream, so we can perform transformations on each paging generation

    // first convert items in stream to UiModel.Item
    PagingData<UiModel.ItemModel> itemModelPagingData = PagingDataTransforms.map(
            itemPagingData, bgExecutor, UiModel.ItemModel::new);

    // Now insert UiModel.Separators, which makes the PagingData of generic type UiModel
    return PagingDataTransforms.insertSeparators(
            itemModelPagingData, bgExecutor,
            (@Nullable UiModel.ItemModel before, @Nullable UiModel.ItemModel after) -> {
                if (after != null && (before == null
                        || before.item.label.charAt(0) != after.item.label.charAt(0))) {
                    // separator - after is first item that starts with its first letter
                    return new UiModel.SeparatorModel(
                            Character.toUpperCase(after.item.label.charAt(0)));
                } else {
                    // no separator - either end of list, or first
                    // letters of items are the same
                    return null;
                }
            });
});

public class UiModel {
    static class ItemModel extends UiModel {
        public Item item;
        ItemModel(Item item) {
            this.item = item;
        }
    }
    static class SeparatorModel extends UiModel {
        public char character;
        SeparatorModel(char character) {
            this.character = character;
        }
    }
}

fun <T : R, R : Any> PagingData<T>.insertSeparatorsAsync(
    generator: AsyncFunction<AdjacentItems<T>, R?>,
    executor: Executor
): PagingData<R>

Returns a PagingData containing each original element, with an optional separator generated by generator, given the elements before and after (or null, in boundary conditions).

Note that this transform is applied asynchronously, as pages are loaded. Potential separators between pages are only computed once both pages are loaded.

import androidx.paging.AdjacentItems
import androidx.paging.insertSeparators
import androidx.paging.insertSeparatorsAsync
import androidx.paging.rxjava2.insertSeparatorsAsync

/*
 * Create letter separators in an alphabetically sorted list.
 *
 * For example, if the input is:
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map { pagingData ->
    // map outer stream, so we can perform transformations on each paging generation
    pagingData.insertSeparatorsAsync(
        AsyncFunction<AdjacentItems<String>, String?> {
            Futures.submit(
                Callable<String?> {
                    val (before, after) = it!!
                    if (after != null && before?.first() != after.first()) {
                        // separator - after is first item that starts with its first letter
                        after.first().uppercaseChar().toString()
                    } else {
                        // no separator - either end of list, or first letters of before/after are the same
                        null
                    }
                },
                executor
            )
        },
        executor
    )
}

import androidx.paging.AdjacentItems
import androidx.paging.insertSeparators
import androidx.paging.insertSeparatorsAsync
import androidx.paging.map
import androidx.paging.rxjava2.insertSeparatorsAsync

open class UiModel
data class ItemUiModel(val item: Item) : UiModel()
data class SeparatorUiModel(val char: Char) : UiModel()

/*
 * Create letter separators in an alphabetically sorted list of Items, with UiModel objects.
 *
 * For example, if the input is (each an `Item`):
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output a list of UiModels corresponding to:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map { pagingData ->
    // map outer stream, so we can perform transformations on each paging generation
    pagingData
        .map { item ->
            ItemUiModel(item) // convert items in stream to ItemUiModel
        }
        .insertSeparatorsAsync(
            AsyncFunction<AdjacentItems<ItemUiModel>, UiModel?> {
                Futures.submit(
                    Callable<UiModel> {
                        val (before, after) = it!!
                        if (after != null &&
                            before?.item?.label?.first() != after.item.label.first()
                        ) {
                            // separator - after is first item that starts with its first letter
                            SeparatorUiModel(after.item.label.first().uppercaseChar())
                        } else {
                            // no separator - either end of list, or first letters of before/after are the same
                            null
                        }
                    },
                    executor
                )
            },
            executor
        )
}

fun <T : Any, R : Any> PagingData<T>.map(transform: suspend (T) -> R): PagingData<R>

Returns a PagingData containing the result of applying the given transform to each element, as it is loaded.

fun <T : Any, R : Any> PagingData<T>.map(executor: Executor, transform: (T) -> R): PagingData<R>

Returns a PagingData containing the result of applying the given transform to each element, as it is loaded.

fun <T : Any, R : Any> PagingData<T>.mapAsync(
    transform: AsyncFunction<T, R>,
    executor: Executor
): PagingData<R>

Returns a PagingData containing the result of applying the given transform to each element, as it is loaded.

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toFlowable(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null,
    backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST
): Flowable<PagedList<Value>>

Constructs a Flowable<PagedList>, from this DataSource.Factory, convenience for RxPagedListBuilder.

The returned Flowable will already be subscribed on the fetchScheduler, and will perform all loading on that scheduler. It will already be observed on notifyScheduler, and will dispatch new PagedLists, as well as their updates to that scheduler.

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toFlowable(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null,
    backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST
): Flowable<PagedList<Value>>

Constructs a Flowable<PagedList>, from this PagingSource factory, convenience for RxPagedListBuilder.

The returned Flowable will already be subscribed on the fetchScheduler, and will perform all loading on that scheduler. It will already be observed on notifyScheduler, and will dispatch new PagedLists, as well as their updates to that scheduler.

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toFlowable(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null,
    backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST
): Flowable<PagedList<Value>>

Constructs a Flowable<PagedList>, from this DataSource.Factory, convenience for RxPagedListBuilder.

The returned Flowable will already be subscribed on the fetchScheduler, and will perform all loading on that scheduler. It will already be observed on notifyScheduler, and will dispatch new PagedLists, as well as their updates to that scheduler.

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toFlowable(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null,
    backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST
): Flowable<PagedList<Value>>

Constructs a Flowable<PagedList>, from this PagingSource factory, convenience for RxPagedListBuilder.

The returned Flowable will already be subscribed on the fetchScheduler, and will perform all loading on that scheduler. It will already be observed on notifyScheduler, and will dispatch new PagedLists, as well as their updates to that scheduler.

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toLiveData(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchExecutor: Executor = ArchTaskExecutor.getIOThreadExecutor()
): LiveData<PagedList<Value>>

Constructs a LiveData<PagedList>, from this DataSource.Factory, convenience for LivePagedListBuilder.

No work (such as loading) is done immediately, the creation of the first PagedList is deferred until the LiveData is observed.

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toLiveData(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchExecutor: Executor = ArchTaskExecutor.getIOThreadExecutor()
): LiveData<PagedList<Value>>

Constructs a LiveData<PagedList>, from this DataSource.Factory, convenience for LivePagedListBuilder.

No work (such as loading) is done immediately, the creation of the first PagedList is deferred until the LiveData is observed.

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toLiveData(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    coroutineScope: CoroutineScope = GlobalScope,
    fetchDispatcher: CoroutineDispatcher = ArchTaskExecutor.getIOThreadExecutor()
        .asCoroutineDispatcher()
): LiveData<PagedList<Value>>

Constructs a LiveData<PagedList>, from this PagingSource factory, convenience for LivePagedListBuilder.

No work (such as loading) is done immediately, the creation of the first PagedList is deferred until the LiveData is observed.

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toLiveData(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    coroutineScope: CoroutineScope = GlobalScope,
    fetchDispatcher: CoroutineDispatcher = ArchTaskExecutor.getIOThreadExecutor()
        .asCoroutineDispatcher()
): LiveData<PagedList<Value>>

Constructs a LiveData<PagedList>, from this PagingSource factory, convenience for LivePagedListBuilder.

No work (such as loading) is done immediately, the creation of the first PagedList is deferred until the LiveData is observed.

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toObservable(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null
): Observable<PagedList<Value>>

Constructs a Observable<PagedList> from this DataSource.Factory, convenience for RxPagedListBuilder.

The returned Observable will already be subscribed on the fetchScheduler, and will perform all loading on that scheduler. It will already be observed on notifyScheduler, and will dispatch new PagedLists, as well as their updates to that scheduler.

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toObservable(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null
): Observable<PagedList<Value>>

Constructs a Observable<PagedList> from this PagingSource factory, convenience for RxPagedListBuilder.

The returned Observable will already be subscribed on the fetchScheduler, and will perform all loading on that scheduler. It will already be observed on notifyScheduler, and will dispatch new PagedLists, as well as their updates to that scheduler.

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toObservable(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null
): Observable<PagedList<Value>>

Constructs a Observable<PagedList> from this DataSource.Factory, convenience for RxPagedListBuilder.

The returned Observable will already be subscribed on the fetchScheduler, and will perform all loading on that scheduler. It will already be observed on notifyScheduler, and will dispatch new PagedLists, as well as their updates to that scheduler.

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toObservable(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null
): Observable<PagedList<Value>>

Constructs a Observable<PagedList> from this PagingSource factory, convenience for RxPagedListBuilder.

The returned Observable will already be subscribed on the fetchScheduler, and will perform all loading on that scheduler. It will already be observed on notifyScheduler, and will dispatch new PagedLists, as well as their updates to that scheduler.

val Pager<Key, Value>.liveData: LiveData<PagingData<Value>>

A LiveData of PagingData, which mirrors the stream provided by Pager.flow, but exposes it as a LiveData.

NOTE: Instances of PagingData emitted by this LiveData are not re-usable and cannot be submitted multiple times. This is especially relevant because LiveData will replays the latest value downstream. To ensure you get a new instance of PagingData for each downstream observer, you should use the cachedIn operator which multicasts the LiveData in a way that returns a new instance of PagingData with cached data pre-loaded.