diff -r 2c3cc4b01880 -r c16ac7a2eba4 test/jdk/jdk/jfr/event/runtime/TestFlush.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/jdk/jfr/event/runtime/TestFlush.java	Wed Oct 30 19:43:52 2019 +0100
@@ -0,0 +1,166 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.event.runtime;
+
+import java.util.concurrent.CountDownLatch;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import jdk.jfr.Event;
+import jdk.jfr.FlightRecorder;
+import jdk.jfr.Period;
+import jdk.jfr.Recording;
+import jdk.jfr.consumer.RecordingStream;
+import jdk.jfr.consumer.RecordedEvent;
+
+import jdk.test.lib.Asserts;
+import jdk.test.lib.jfr.EventNames;
+
+/**
+ * @test
+ * @summary Verifies at the metalevel that stream contents are written to ongoing recordings
+ * @key jfr
+ * @requires vm.hasJFR
+ * @library /test/lib
+ * @run main/othervm -Xlog:jfr+system+streaming=trace jdk.jfr.event.runtime.TestFlush
+ */
+public class TestFlush {
+    private static boolean flushEventAck = false;
+
+    @Period("2 s")
+    static class ZebraEvent extends Event {
+    }
+    static class CatEvent extends Event {
+    }
+    static class DogEvent extends Event {
+    }
+    static class MouseEvent extends Event {
+    }
+
+    public static void main(String... args) throws InterruptedException {
+        CountDownLatch dogLatch = new CountDownLatch(1);
+        CountDownLatch catLatch = new CountDownLatch(1);
+        CountDownLatch mouseLatch = new CountDownLatch(1);
+        CountDownLatch zebraLatch = new CountDownLatch(3);
+
+        FlightRecorder.addPeriodicEvent(ZebraEvent.class, () -> {
+            ZebraEvent ze = new ZebraEvent();
+            ze.commit();
+        });
+
+        try (RecordingStream rs = new RecordingStream()) {
+            rs.enable(EventNames.Flush);
+            rs.enable(EventNames.FlushStorage);
+            rs.enable(EventNames.FlushStacktrace);
+            rs.enable(EventNames.FlushStringPool);
+            rs.enable(EventNames.FlushMetadata);
+            rs.enable(EventNames.FlushTypeSet);
+            rs.onEvent(e -> {
+                switch (e.getEventType().getName()) {
+                    case EventNames.Flush:
+                        flushEventAck = true;
+                    case EventNames.FlushStorage:
+                    case EventNames.FlushStacktrace:
+                    case EventNames.FlushStringPool:
+                    case EventNames.FlushMetadata:
+                    case EventNames.FlushTypeSet:
+                        validateFlushEvent(e);
+                        return;
+                }
+                if (e.getEventType().getName().equals(CatEvent.class.getName())) {
+                    System.out.println("Found cat!");
+                    catLatch.countDown();
+                    return;
+                }
+                if (e.getEventType().getName().equals(DogEvent.class.getName())) {
+                    System.out.println("Found dog!");
+                    dogLatch.countDown();
+                    return;
+                }
+                if (e.getEventType().getName().equals(ZebraEvent.class.getName())) {
+                    System.out.println("Found zebra!");
+                    zebraLatch.countDown();
+                    return;
+                }
+                if (e.getEventType().getName().equals(MouseEvent.class.getName())) {
+                    System.out.println("Found mouse!");
+                    mouseLatch.countDown();
+                    return;
+                }
+                System.out.println("Unexpected event: " + e.getEventType().getName());
+            });
+
+            rs.startAsync();
+
+            try (Recording r1 = new Recording()) {
+                r1.start();
+                MouseEvent me = new MouseEvent();
+                me.commit();
+                System.out.println("Mouse emitted");
+                mouseLatch.await();
+                try (Recording r2 = new Recording()) { // force chunk rotation in stream
+                    r2.start();
+                    DogEvent de = new DogEvent();
+                    de.commit();
+                    System.out.println("Dog emitted");
+                    dogLatch.await();
+                    CatEvent ce = new CatEvent();
+                    ce.commit();
+                    System.out.println("Cat emitted");
+                    catLatch.await();
+                    zebraLatch.await();
+                    acknowledgeFlushEvent();
+                }
+            }
+        }
+    }
+
+    private static void printEvent(RecordedEvent re) {
+        System.out.println(re.getEventType().getName());
+        System.out.println(re.getStartTime().toEpochMilli());
+        System.out.println(re.getEndTime().toEpochMilli());
+    }
+
+    private static void printFlushEvent(RecordedEvent re) {
+        printEvent(re);
+        System.out.println("flushID: " + (long) re.getValue("flushId"));
+        System.out.println("elements: " + (long) re.getValue("elements"));
+        System.out.println("size: " + (long) re.getValue("size"));
+    }
+
+    private static void validateFlushEvent(RecordedEvent re) {
+        printFlushEvent(re);
+        Asserts.assertTrue(re.getEventType().getName().contains("Flush"), "invalid Event type");
+        Asserts.assertGT((long) re.getValue("flushId"), 0L, "Invalid flush ID");
+        Asserts.assertGT((long) re.getValue("elements"), 0L, "No elements");
+        Asserts.assertGT((long) re.getValue("size"), 0L, "Empty size");
+    }
+
+    private static void acknowledgeFlushEvent() {
+        Asserts.assertTrue(flushEventAck, "No Flush event");
+    }
+}