trace2.go

func Start(w io.Writer) error {
 tracing.Lock()
 defer tracing.Unlock()
if err := runtime.StartTrace(); err != nil {
  return err
 }
 go func() {
  for {
   data := runtime.ReadTrace()
   if data == nil {
    break
   }
   w.Write(data)
  }
 }()
 tracing.enabled.Store(true)
 return nil
}​