// A running goroutine stole P0 at the generation boundary.
	b1 := g.Batch(trace.ThreadID(1), 0)
	b1.Event("ProcStatus", trace.ProcID(2), go122.ProcRunning)
	b1.Event("GoStatus", trace.GoID(2), trace.ThreadID(1), go122.GoRunning)
	b1.Event("ProcStatus", trace.ProcID(0), go122.ProcSyscallAbandoned)
	b1.Event("ProcSteal", trace.ProcID(0), testgen.Seq(1), trace.ThreadID(0))

const (
	GoUndetermined GoState = iota // No information is known about the goroutine.
	GoNotExist                    // Goroutine does not exist.
	GoRunnable                    // Goroutine is runnable but not running.
	GoRunning                     // Goroutine is running.
	GoWaiting                     // Goroutine is waiting on something to happen.
	GoSyscall                     // Goroutine is in a system call.
)

		s = goStateTransition(GoID(e.base.args[0]), GoRunnable, GoRunning)
	case go122.EvGoDestroy:
		s = goStateTransition(e.ctx.G, GoRunning, GoNotExist)
		s.Stack = e.Stack() // This event references the resource the event happened on.
	case go122.EvGoDestroySyscall:
		s = goStateTransition(e.ctx.G, GoSyscall, GoNotExist)
	case go122.EvGoStop:
		s = goStateTransition(e.ctx.G, GoRunning, GoRunnable)

		return curCtx, false, err
	}
	// If we have a goroutine, it must be running.
	if state, ok := o.gStates[curCtx.G]; ok && state.status != go122.GoRunning {
		return curCtx, false, fmt.Errorf("%s event for goroutine that's not %s", go122.EventString(ev.typ), GoRunning)
	}
	// This goroutine created another. Add a state for it.
	newgid := GoID(ev.args[0])
	if _, ok := o.gStates[newgid]; ok {

	g1 := t.Generation(1)

	// A running goroutine blocks.
	b10 := g1.Batch(trace.ThreadID(0), 0)
	b10.Event("ProcStatus", trace.ProcID(0), go122.ProcRunning)
	b10.Event("GoStatus", trace.GoID(1), trace.ThreadID(0), go122.GoRunning)
	b10.Event("GoStop", "whatever", testgen.NoStack)

	// The running goroutine gets unblocked.
	b11 := g1.Batch(trace.ThreadID(1), 0)
	b11.Event("ProcStatus", trace.ProcID(1), go122.ProcRunning)

	}
	if from == trace.GoNotExist && to == trace.GoRunnable {
		// Goroutine was created.
		gs.created(ev.Time(), ev.Goroutine(), ev.Stack())
	}
	if from == trace.GoSyscall && to != trace.GoRunning {
		// Exiting blocked syscall.
		gs.syscallEnd(ev.Time(), true, ctx)
		gs.blockedSyscallEnd(ev.Time(), ev.Stack(), ctx)
	} else if from == trace.GoSyscall {
		// Check if we're exiting a syscall in a non-blocking way.

		Experiment:   AllocFree,
	},
}

type GoStatus uint8

const (
	GoBad GoStatus = iota
	GoRunnable
	GoRunning
	GoSyscall
	GoWaiting
)

func (s GoStatus) String() string {
	switch s {
	case GoRunnable:
		return "Runnable"
	case GoRunning:
		return "Running"
	case GoSyscall:
		return "Syscall"
	case GoWaiting:
		return "Waiting"
	}
	return "Bad"
}

		// Goroutine was created.
		gs.created(ev.Time(), ev.Thread(), ev.Stack())
	}
	if from == trace.GoSyscall {
		// Exiting syscall.
		gs.syscallEnd(ev.Time(), to != trace.GoRunning, ctx)
	}

	// Handle syscalls.
	if to == trace.GoSyscall {
		start := ev.Time()
		if from == trace.GoUndetermined {
			// Back-date the event to the start of the trace.
			start = ctx.startTime
		}

					regions := creatorG.activeRegions
					s := regions[len(regions)-1]
					g.activeRegions = []*UserRegionSummary{{TaskID: s.TaskID, Start: ev}}
				}
				s.gs[g.ID] = g
			case GoRunning:
				// Record execution time as we transition out of running
				g.ExecTime += ev.Time().Sub(g.lastStartTime)
				g.lastStartTime = 0
			case GoWaiting:
				// Record block time as we transition out of waiting.

			return Event{}, errSkip
		}
		mappedType = go122.EvGoCreate
	case oldtrace.EvGoStart:
		if it.preInit {
			mappedType = go122.EvGoStatus
			mappedArgs = timedEventArgs{ev.Args[0], ^uint64(0), uint64(go122.GoRunning)}
			delete(it.createdPreInit, GoID(ev.Args[0]))
		} else {
			mappedType = go122.EvGoStart
		}
	case oldtrace.EvGoStartLabel:
		it.extra = []Event{{
			ctx: schedCtx{
				G: GoID(ev.G),