introduce resumeTokenChanged into 6.x

Author: 3150

lib/cursor/ChangeStream.js

@@ -75,7 +75,7 @@ class ChangeStream extends EventEmitter {
       this.closed = true;
     });
 
-    ['close', 'change', 'end', 'error'].forEach(ev => {
+    ['close', 'change', 'end', 'error', 'resumeTokenChanged'].forEach(ev => {
       this.driverChangeStream.on(ev, data => {
         // Sometimes Node driver still polls after close, so
         // avoid any uncaught exceptions due to closed change streams

test/model.test.js

@@ -5406,6 +5406,20 @@ describe('Model', function() {
           assert.equal(changeData.operationType, 'insert');
           assert.equal(changeData.fullDocument.name, 'Child');
         });
+
+        it('bubbles up resumeTokenChanged events (gh-14349)', async function() {
+          const MyModel = db.model('Test', new Schema({ name: String }));
+
+          const resumeTokenChangedEvent = new Promise(resolve => {
+            changeStream = MyModel.watch();
+            listener = data => resolve(data);
+            changeStream.once('resumeTokenChanged', listener);
+          });
+
+          await MyModel.create({ name: 'test' });
+          const { _data } = await resumeTokenChangedEvent;
+          assert.ok(_data);
+        });
       });
 
       describe('sessions (gh-6362)', function() {