code: func (t *Task) Hash() uint64 {
  	h := fnv.New64a()
  	fmt.Fprintf(h, "%s\n%s\n%s\n%s\n%d",
  		t.ServiceName,
  		t.JobName,
  		t.DataCenter,
  		t.HostName,
  		t.TaskNum)
  	return h.Sum64()
  }
docs: // Hash returns a uint64 hash of this target.