ExecTime time.Duration // Total execution time of all goroutines in this group.
		}
		// Accumulate groups by Name.
		groupsByName := make(map[string]goroutineGroup)
		for _, summary := range summaries {
			group := groupsByName[summary.Name]
			group.Name = summary.Name
			group.N++
			group.ExecTime += summary.ExecTime
			groupsByName[summary.Name] = group
		}

	if sum < s.TotalTime {
		return s.TotalTime - sum
	}
	return 0
}

// sub returns the stats v-s.
func (s GoroutineExecStats) sub(v GoroutineExecStats) (r GoroutineExecStats) {
	r = s.clone()
	r.ExecTime -= v.ExecTime
	r.SchedWaitTime -= v.SchedWaitTime
	for reason := range s.BlockTimeByReason {
		r.BlockTimeByReason[reason] -= v.BlockTimeByReason[reason]
	}
	r.SyscallTime -= v.SyscallTime

			}
		}
	default:
		t.Errorf("unexpected want end event type: %s", wantEnd)
	}
}

func basicGoroutineExecStatsChecks(t *testing.T, stats *trace.GoroutineExecStats) {
	if stats.ExecTime < 0 {
		t.Error("found negative ExecTime")
	}
	if stats.SchedWaitTime < 0 {
		t.Error("found negative SchedWaitTime")
	}
	if stats.SyscallTime < 0 {
		t.Error("found negative SyscallTime")
	}