code: func (th *timeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
  	t, _ := trace.NewContext(context.Background(), "webserver", "servehttp")
  	defer t.Finish()
  
  	tm := time.Now().Format(th.format)
  	// log to the trace
  	t.LazyPrintf("time %v", tm)
  	w.Write([]byte("The time is: " + tm))
  }
docs: // Inside the handler, use traces to capture request specific events and timings
  // and the el member to log service specific events - like failures