Android分页库java.lang.illegalargumentException:需要MainthreaDexecutor

我正在使用Android分页库 androidx.paging:paging-runtime:2.0.0 建立一个列表。问题是当我想建立 PagedList ( LivePagedList 我有一个错误:

java.lang.IllegalArgumentException: MainThreadExecutor required
at androidx.paging.PagedList$Builder.build(PagedList.java:355)

但我看不出来 setMainThreadExecutor 方法可用,只有 setFetchExecutor :

    val result = list.filter { it.desc?.contains(query, ignoreCase = true) == true }
    val dataSource = MyDataSource(result)
    val mainHandler = Handler(Looper.getMainLooper())
    val pagedList: PagedList<MyDetails> = PagedList.Builder<Int, MyDetails>(dataSource, 500).setFetchExecutor { mainHandler.post(it) }
                .build()

谁知道这里有什么问题?