* cancelled.
     */
    @CheckForNull Executor delegate;

    /**
     * Set before calling delegate.execute(); set to null once run, so that it can be GCed; this
     * object may live on after, if submitAsync returns an incomplete future.
     */
    @CheckForNull Runnable task;

        captureOutput.flush()
        super.flush()
    }

    fun stop() = safely {
        isCapturing!!.remove()
        // Give a chance for other threads' weak references to the local to be GCed if any
        isCapturing = null
    }

    private
    fun safely(block: () -> Unit) =
        try {
            synchronized(this, block)
        } catch (ex: InterruptedException) {

	// N.B. Only one GC can be running at a time, so this is naturally
	// serialized by the caller.
	trace.seqGC++
}

// GCDone traces a GCEnd event.
//
// Must be emitted by an actively running goroutine on an active P. This restriction can be changed
// easily and only depends on where it's currently called.
func (tl traceLocker) GCDone() {

     * cancelled.
     */
    @CheckForNull Executor delegate;

    /**
     * Set before calling delegate.execute(); set to null once run, so that it can be GCed; this
     * object may live on after, if submitAsync returns an incomplete future.
     */
    @CheckForNull Runnable task;

	expectNonce(res.Nonce, v3.ClusterType)
	// Types we are not subscribed to are also updated
	expectNonce(res.Nonce, v3.RouteType)
	// Ledger has no explicit close, only through GC, so we need to make sure it can be GCed
	s.Env().SetLedger(nil)
	s.Discovery.StatusReporter = nil

GoStart dt=7 g=24 g_seq=13
GoLabel dt=1 label_string=2
STWBegin dt=4128 kind_string=23 stack=37
GoUnblock dt=64 g=25 g_seq=8 stack=38
HeapAlloc dt=25 heapalloc_value=16970376
GoUnblock dt=24 g=3 g_seq=5 stack=39
GCEnd dt=6 gc_seq=6
HeapGoal dt=7 heapgoal_value=34360936
ProcsChange dt=46 procs_value=8 stack=40
STWEnd dt=49
GoBlock dt=756 reason_string=15 stack=27
GoStart dt=10 g=3 g_seq=6

       */
      ListenableFuture<? extends T> inputFuture = requireNonNull(inputFutures[inputFutureIndex]);
      // Null out our reference to this future, so it can be GCed
      inputFutures[inputFutureIndex] = null;
      for (int i = delegateIndex; i < delegates.size(); i++) {
        if (delegates.get(i).setFuture(inputFuture)) {
          recordCompletion();

	gcsToEmit := []struct {
		symName string
		symKind sym.SymKind
		gcEnd   int64
	}{
		{"runtime.gcdata", sym.SDATA, dataGcEnd},
		{"runtime.gcbss", sym.SBSS, bssGcEnd},
	}
	for _, g := range gcsToEmit {
		var gc GCProg
		gc.Init(ctxt, g.symName)
		for _, s := range state.data[g.symKind] {
			gc.AddSym(s)
		}
		gc.End(g.gcEnd)
	}

	/* pointer-free bss */

       */
      ListenableFuture<? extends T> inputFuture = requireNonNull(inputFutures[inputFutureIndex]);
      // Null out our reference to this future, so it can be GCed
      inputFutures[inputFutureIndex] = null;
      for (int i = delegateIndex; i < delegates.size(); i++) {
        if (delegates.get(i).setFuture(inputFuture)) {
          recordCompletion();

GoUnblock dt=6 g=100 g_seq=6 stack=22
GoUnblock dt=29 g=86 g_seq=6 stack=23
HeapAlloc dt=53 heapalloc_value=103773088
GoStatus dt=10 g=3 m=18446744073709551615 gstatus=4
GoUnblock dt=7 g=3 g_seq=1 stack=24
GCEnd dt=3 gc_seq=5
HeapGoal dt=6 heapgoal_value=207987496
ProcsChange dt=45 procs_value=48 stack=25
STWEnd dt=399
GoUnblock dt=5992 g=130 g_seq=6 stack=26
GCMarkAssistEnd dt=9