size += binary.PutUvarint(buf[:], uint64(len(e.Data)))
		size += len(e.Data)
	}
	return size
}

type countingReader struct {
	io.Reader
	bytesRead int
}

func (r *countingReader) Read(b []byte) (int, error) {
	n, err := r.Reader.Read(b)
	r.bytesRead += n
	return n, err

	for {
		ev, err := r.ReadEvent()
		if err == io.EOF {
			validBytes = cr.bytesRead.Load()
			validEvents = len(t.events)
			break
		}
		if err != nil {
			t.err = err
			break
		}
		t.events = append(t.events, ev)
		s.Event(&t.events[len(t.events)-1])

		if ev.Kind() == trace.EventSync {
			validBytes = cr.bytesRead.Load()
			validEvents = len(t.events)
		}
	}