Enable `Streamable` for `Pageable` use.

Closes #3397

src/main/java/org/springframework/data/repository/util/QueryExecutionConverters.java

@@ -100,6 +100,7 @@ public abstract class QueryExecutionConverters {
 		ALLOWED_PAGEABLE_TYPES.add(Slice.class);
 		ALLOWED_PAGEABLE_TYPES.add(Page.class);
 		ALLOWED_PAGEABLE_TYPES.add(List.class);
+		ALLOWED_PAGEABLE_TYPES.add(Streamable.class);
 		ALLOWED_PAGEABLE_TYPES.add(Window.class);
 		ALLOWED_PAGEABLE_TYPES.add(SearchResults.class);
 

src/test/java/org/springframework/data/repository/query/QueryMethodUnitTests.java

@@ -206,6 +206,16 @@ class QueryMethodUnitTests {
 		assertThat(new QueryMethod(method, repositoryMetadata, factory, DefaultParameters::new).isStreamQuery()).isTrue();
 	}
 
+	@Test // GH-3397
+	void doesNotRejectStreamableForPagination() throws Exception {
+
+		RepositoryMetadata repositoryMetadata = new DefaultRepositoryMetadata(SampleRepository.class);
+		var method = SampleRepository.class.getMethod("streamable", Pageable.class);
+
+		assertThat(new QueryMethod(method, repositoryMetadata, factory, DefaultParameters::new).isCollectionQuery())
+				.isTrue();
+	}
+
 	@Test // DATACMNS-716
 	void doesNotRejectCompletableFutureQueryForSingleEntity() throws Exception {
 
@@ -445,6 +455,8 @@ class QueryMethodUnitTests {
 
 		Stream<String> streaming(Pageable pageable);
 
+		Streamable<String> streamable(Pageable pageable);
+
 		// DATACMNS-716
 		CompletableFuture<User> returnsCompletableFutureForSingleEntity();