Close all per-generation channels on Pager invalidation

Fixes: 147676632
Test: ./gradlew paging:paging-common:test
Change-Id: I8857fce3a8a42181a80d4a58b00b3e4f4b341e01

diff --git a/paging/common/api/current.txt b/paging/common/api/current.txt
index 60851f0..0f0964f 100644
--- a/paging/common/api/current.txt
+++ b/paging/common/api/current.txt

@@ -5,6 +5,9 @@
     method public static <T> kotlinx.coroutines.flow.Flow<androidx.paging.PagingData<T>> cachedIn(kotlinx.coroutines.flow.Flow<androidx.paging.PagingData<T>>, kotlinx.coroutines.CoroutineScope scope);
   }
 
+  public final class CancelableChannelFlowKt {
+  }
+
   public abstract class DataSource<Key, Value> {
     method @AnyThread public void addInvalidatedCallback(androidx.paging.DataSource.InvalidatedCallback onInvalidatedCallback);
     method @AnyThread public final void addInvalidatedCallback(kotlin.jvm.functions.Function0<kotlin.Unit> onInvalidatedCallback);