Convert PositionalDataSource to coroutines

Test: ./gradlew paging:paging-common:check
Change-Id: I3ec699b5a6b53a6ed0b4f332647cb2330d620b3a

diff --git a/paging/common/api/current.txt b/paging/common/api/current.txt
index a372c63..e91e797 100644
--- a/paging/common/api/current.txt
+++ b/paging/common/api/current.txt

@@ -312,6 +312,7 @@
     method public static final int computeInitialLoadSize(androidx.paging.PositionalDataSource.LoadInitialParams params, int initialLoadPosition, int totalCount);
     method public final suspend Object load$lintWithKotlin(androidx.paging.DataSource.Params<java.lang.Integer> params, kotlin.coroutines.Continuation<? super androidx.paging.DataSource.BaseResult<T>> p);
     method @WorkerThread public abstract void loadInitial(androidx.paging.PositionalDataSource.LoadInitialParams params, androidx.paging.PositionalDataSource.LoadInitialCallback<T> callback);
+    method @VisibleForTesting public final suspend Object loadInitial$lintWithKotlin(androidx.paging.PositionalDataSource.LoadInitialParams params, kotlin.coroutines.Continuation<? super androidx.paging.PositionalDataSource.InitialResult<T>> p);
     method @WorkerThread public abstract void loadRange(androidx.paging.PositionalDataSource.LoadRangeParams params, androidx.paging.PositionalDataSource.LoadRangeCallback<T> callback);
     method public final <V> androidx.paging.PositionalDataSource<V> map(androidx.arch.core.util.Function<T,V> function);
     method public final <V> androidx.paging.PositionalDataSource<V> map(kotlin.jvm.functions.Function1<? super T,? extends V> function);