gg := new(goroutineGenerator)
	rg := func(ev *trace.Event) trace.GoID {
		return ev.Goroutine()
	}
	gg.stackSampleGenerator.getResource = rg
	gg.logEventGenerator.getResource = rg
	gg.gStates = make(map[trace.GoID]*gState[trace.GoID])
	gg.focus = focus
	gg.filter = filter

	// Enable a filter on the emitter.
	if filter != nil {

}

func newThreadGenerator() *threadGenerator {
	tg := new(threadGenerator)
	rg := func(ev *trace.Event) trace.ThreadID {
		return ev.Thread()
	}
	tg.stackSampleGenerator.getResource = rg
	tg.logEventGenerator.getResource = rg
	tg.gStates = make(map[trace.GoID]*gState[trace.ThreadID])
	tg.threads = make(map[trace.ThreadID]struct{})
	return tg
}

func (g *threadGenerator) Sync() {
	g.globalRangeGenerator.Sync()

type stackSampleGenerator[R resource] struct {
	// getResource is a function to extract a resource ID from a stack sample event.
	getResource func(*trace.Event) R
}

// StackSample implements a stack sample event handler. It expects ev to be one such event.
func (g *stackSampleGenerator[R]) StackSample(ctx *traceContext, ev *trace.Event) {
	id := g.getResource(ev)
	if id == R(noResource) {

	maxProc   trace.ProcID
}

func newProcGenerator() *procGenerator {
	pg := new(procGenerator)
	rg := func(ev *trace.Event) trace.ProcID {
		return ev.Proc()
	}
	pg.stackSampleGenerator.getResource = rg
	pg.logEventGenerator.getResource = rg
	pg.gStates = make(map[trace.GoID]*gState[trace.ProcID])
	pg.inSyscall = make(map[trace.ProcID]*gState[trace.ProcID])
	return pg
}

func (g *procGenerator) Sync() {