--- a/src/hotspot/share/jfr/recorder/checkpoint/jfrMetadataEvent.hpp	Mon Sep 02 21:08:41 2019 +0200
+++ b/src/hotspot/share/jfr/recorder/checkpoint/jfrMetadataEvent.hpp	Tue Sep 03 11:48:31 2019 +0200
@@ -37,6 +37,8 @@
 //
 class JfrMetadataEvent : AllStatic {
  public:
+  static void lock();
+  static void unlock();
   static void write(JfrChunkWriter& writer);
   static void update(jbyteArray metadata);
 };