g.gStates[r.Scope.Goroutine()].rangeActive(r.Name)
	case trace.EventRangeEnd:
		gs := g.gStates[r.Scope.Goroutine()]
		gs.rangeEnd(ev.Time(), r.Name, ev.Stack(), ctx)
	}
}

func (g *goroutineGenerator) GoroutineTransition(ctx *traceContext, ev *trace.Event) {
	st := ev.StateTransition()
	goID := st.Resource.Goroutine()

	// If we haven't seen this goroutine before, create a new
	// gState for it.
	gs, ok := g.gStates[goID]

		g.gStates[r.Scope.Goroutine()].rangeActive(r.Name)
	case trace.EventRangeEnd:
		gs := g.gStates[r.Scope.Goroutine()]
		gs.rangeEnd(ev.Time(), r.Name, ev.Stack(), ctx)
	}
}

func (g *threadGenerator) GoroutineTransition(ctx *traceContext, ev *trace.Event) {
	if ev.Thread() != trace.NoThread {
		if _, ok := g.threads[ev.Thread()]; !ok {
			g.threads[ev.Thread()] = struct{}{}
		}
	}

	st := ev.StateTransition()

		g.gStates[r.Scope.Goroutine()].rangeActive(r.Name)
	case trace.EventRangeEnd:
		gs := g.gStates[r.Scope.Goroutine()]
		gs.rangeEnd(ev.Time(), r.Name, ev.Stack(), ctx)
	}
}

func (g *procGenerator) GoroutineTransition(ctx *traceContext, ev *trace.Event) {
	st := ev.StateTransition()
	goID := st.Resource.Goroutine()

	// If we haven't seen this goroutine before, create a new
	// gState for it.
	gs, ok := g.gStates[goID]

	GlobalMetric(ctx *traceContext, ev *trace.Event)

	// Goroutine parts.
	GoroutineLabel(ctx *traceContext, ev *trace.Event)
	GoroutineRange(ctx *traceContext, ev *trace.Event)
	GoroutineTransition(ctx *traceContext, ev *trace.Event)

	// Proc parts.
	ProcRange(ctx *traceContext, ev *trace.Event)
	ProcTransition(ctx *traceContext, ev *trace.Event)

	// User annotations.

func (e *Emitter) HeapAlloc(ts time.Duration, v uint64) {
	e.heapStats.heapAlloc = v
	e.emitHeapCounters(ts)
}

func (e *Emitter) Focus(id uint64) {
	e.focusResource = id
}

func (e *Emitter) GoroutineTransition(ts time.Duration, from, to GState) {
	e.gstates[from]--
	e.gstates[to]++
	if e.prevGstates == e.gstates {
		return
	}
	if e.tsWithinRange(ts) {
		e.OptionalEvent(&format.Event{