Add ObservableSource.asFlow operator (#1768)

Author: qwwdfsad

reactive/kotlinx-coroutines-rx2/api/kotlinx-coroutines-rx2.api

@@ -29,6 +29,7 @@ public final class kotlinx/coroutines/rx2/RxCompletableKt {
 
 public final class kotlinx/coroutines/rx2/RxConvertKt {
 	public static final fun asCompletable (Lkotlinx/coroutines/Job;Lkotlin/coroutines/CoroutineContext;)Lio/reactivex/Completable;
+	public static final fun asFlow (Lio/reactivex/ObservableSource;)Lkotlinx/coroutines/flow/Flow;
 	public static final fun asMaybe (Lkotlinx/coroutines/Deferred;Lkotlin/coroutines/CoroutineContext;)Lio/reactivex/Maybe;
 	public static final fun asObservable (Lkotlinx/coroutines/channels/ReceiveChannel;Lkotlin/coroutines/CoroutineContext;)Lio/reactivex/Observable;
 	public static final fun asSingle (Lkotlinx/coroutines/Deferred;Lkotlin/coroutines/CoroutineContext;)Lio/reactivex/Single;