if gs.executing != R(noResource) {
		// If we're executing, start the slice from here.
		gs.activeRanges[name] = activeRange{ts, stack}
	} else {
		// If the goroutine isn't executing, there's no place for
		// us to create a slice from. Wait until it starts executing.
		gs.activeRanges[name] = activeRange{0, stack}
	}
}

// rangeActive indicates that a special range of time has been in progress.

		// (i.e. the G has been blocked in a syscall).
		gs.syscallBegin(start, goID, ev.Stack())
	}

	// Note down the goroutine transition.
	_, inMarkAssist := gs.activeRanges["GC mark assist"]
	ctx.GoroutineTransition(ctx.elapsed(ev.Time()), viewerGState(from, inMarkAssist), viewerGState(to, inMarkAssist))
}

func (g *goroutineGenerator) ProcRange(ctx *traceContext, ev *trace.Event) {

		// (i.e. the G has been blocked in a syscall).
		gs.syscallBegin(start, ev.Thread(), ev.Stack())
	}

	// Note down the goroutine transition.
	_, inMarkAssist := gs.activeRanges["GC mark assist"]
	ctx.GoroutineTransition(ctx.elapsed(ev.Time()), viewerGState(from, inMarkAssist), viewerGState(to, inMarkAssist))
}

func (g *threadGenerator) ProcTransition(ctx *traceContext, ev *trace.Event) {

	if from == trace.GoSyscall && didNotBlock {
		gs.syscallEnd(ev.Time(), false, ctx)
		delete(g.inSyscall, ev.Proc())
	}

	// Note down the goroutine transition.
	_, inMarkAssist := gs.activeRanges["GC mark assist"]
	ctx.GoroutineTransition(ctx.elapsed(ev.Time()), viewerGState(from, inMarkAssist), viewerGState(to, inMarkAssist))
}

func (g *procGenerator) ProcTransition(ctx *traceContext, ev *trace.Event) {

		g.ranges = make(map[trace.Range]activeRange)
	}
	r := ev.Range()
	switch ev.Kind() {
	case trace.EventRangeBegin:
		g.ranges[r] = activeRange{ev.Time(), ev.Stack()}
	case trace.EventRangeActive:
		// If we've seen a Sync event, then Active events are always redundant.
		if !g.seenSync {
			// Otherwise, they extend back to the start of the trace.
			g.ranges[r] = activeRange{ctx.startTime, ev.Stack()}
		}

	}
	s.inFlight = append(s.inFlight, typ)
	return nil
}

// activeRange marks special range in time on the goroutine as active in the
// initial generation, or confirms that it is indeed active in later generations.
func (s *rangeState) activeRange(typ rangeType, isInitialGen bool) error {
	if isInitialGen {
		if s.hasRange(typ) {