* which is a performance optimization. <p>
 *
 * Upon an invocation of {@link InstrumentableClosure#makeEffectivelyInstrumented} the instance must perform
 * all the delayed work and become "effectively instrumented".
 *
 * @see CallInterceptionClosureInstrumentingClassVisitor
 */
@NonNullApi
public interface InstrumentableClosure {
    void makeEffectivelyInstrumented();

     */
    private final Object2IntMap<InstrumentableClosure> currentClosuresEntries = new Object2IntOpenHashMap<>();

    @Override
    public void enterClosure(InstrumentableClosure thisClosure) {
        currentClosuresEntries.mergeInt(thisClosure, 1, Integer::sum);
    }

    @Override
    public void leaveClosure(InstrumentableClosure thisClosure) {

    public static void enterInstrumentedClosure(InstrumentableClosure thisClosure) {
        INSTANCE.enterClosure(thisClosure);
    }

    @SuppressWarnings("unused") // call sites generated by instrumentation in `CallInterceptionClosureInstrumentingClassVisitor`
    public static void leaveInstrumentedClosure(InstrumentableClosure thisClosure) {
        INSTANCE.leaveClosure(thisClosure);
    }

 * ensures call interception if a call is dispatched to them.
 */
@NonNullApi
public interface InstrumentedClosuresTracker {
    void enterClosure(InstrumentableClosure thisClosure);
    void leaveClosure(InstrumentableClosure thisClosure);
    void hitInstrumentedDynamicCall();

        perThreadTracker = ThreadLocal.withInitial(trackerForThread);
    }

    @Override
    public void enterClosure(InstrumentableClosure thisClosure) {
        perThreadTracker.get().enterClosure(thisClosure);
    }

    @Override
    public void leaveClosure(InstrumentableClosure thisClosure) {
        perThreadTracker.get().leaveClosure(thisClosure);
    }

    @Override

 *          the new delegate. This ensures the invariant above.
 *     <li> Adds {@link InstrumentableClosure} to the set of interfaces.
 *     <li> Renames the {@code doCall} methods to {@code doCall$original} and adds new {@code doCall methods} that surrounds the original call with