如何使用新的分页库3实现分页3的ItemKeyedDataSource与RxSupport类似的RxPagingSource

implementation "androidx.paging:paging-runtime:3.0.0"

class MyItemKeyedDataSource : ItemKeyedDataSource<KeyType, ItemType>() {
    override fun loadInitial(params: LoadInitialParams<KeyType>, callback: LoadInitialCallback<ItemType>) {
        // 加载初始数据的逻辑
    }

    override fun loadAfter(params: LoadParams<KeyType>, callback: LoadCallback<ItemType>) {
        // 加载后续数据的逻辑
    }

    override fun loadBefore(params: LoadParams<KeyType>, callback: LoadCallback<ItemType>) {
        // 加载之前数据的逻辑
    }

    override fun getKey(item: ItemType): KeyType {
        // 获取每个数据项的键的逻辑
    }
}

class MyPagingSource : PagingSource<KeyType, ItemType>() {
    override suspend fun load(params: LoadParams<KeyType>): LoadResult<KeyType, ItemType> {
        // 加载数据的逻辑
    }

    override fun getRefreshKey(state: PagingState<KeyType, ItemType>): KeyType? {
        // 获取刷新键的逻辑
    }
}

val pager = Pager(config = PagingConfig(pageSize = 20)) {
    MyPagingSource()
}

val pagingData: Flow<PagingData<ItemType>> = pager.flow.cachedIn(viewModelScope)

class MyAdapter : PagingDataAdapter<ItemType, MyViewHolder>(diffCallback) {
    // 实现ViewHolder和数据绑定的逻辑
}

val adapter = MyAdapter()

pagingData.observe(viewLifecycleOwner) { data ->
    adapter.submitData(viewLifecycleOwner.lifecycle, data)
}