@Override
        final void onClose() {
            final Throwable releaseStack = new Throwable();
            resource.removeReferenceStack(referenceStack, releaseStack);
        }
Does reference counting by putting stacktraces in a map together with an optional context.
Intended only for debugging as it is slow.
Used if system property jdisc.debug.resources=stack

@author baldersheim
jdisc_core/src/main/java/com/yahoo/jdisc/refcount/DebugReferencesWithStack.java