add runningReduce()

lib/src/collection/kt_iterable.dart

@@ -1184,6 +1184,21 @@ extension KtIterableExtensions<T> on KtIterable<T> {
     return accumulator;
   }
 
+  /// Returns a list containing successive accumulation values generated by applying [operation] from left to right to each element and current accumulator value that starts with the first element of this collection.
+  KtList<S> runningReduce<S>(S Function(S acc, T) operation) {
+    final i = iterator();
+    if (!i.hasNext()) {
+      return emptyList();
+    }
+    S accumulator = i.next() as S;
+    final result = mutableListOf<S>()..add(accumulator);
+    while (i.hasNext()) {
+      accumulator = operation(accumulator, i.next());
+      result.add(accumulator);
+    }
+    return result;
+  }
+
   /// Returns a list with elements in reversed order.
   KtList<T> reversed() {
     if (this is KtCollection && (this as KtCollection).size <= 1) {

test/collection/iterable_extensions_test.dart

@@ -1764,6 +1764,20 @@ void testIterable(KtIterable<T> Function<T>() emptyIterable,
     });
   });
 
+  group("runningReduce", () {
+    if (ordered) {
+      test("runningReduce", () {
+        final result = iterableOf<String>(["a", "b", "c", "d"])
+            .runningReduce((String acc, it) => acc + it);
+        expect(result, listOf("a", "ab", "abc", "abcd"));
+      });
+    }
+
+    test("return empty list when list is empty", () {
+      expect(emptyIterable<int>().runningReduce((_, __) => "S"), emptyList());
+    });
+  });
+
   group("reversed", () {
     test("mutliple", () {
       final result = iterableOf([1, 2, 3, 4]).reversed();