code: func NewTracker(label fmt.Stringer, bytesLimit int64) *Tracker {
  	return &Tracker{
  		label:          label,
  		bytesLimit:     bytesLimit,
  		actionOnExceed: &LogOnExceed{},
  	}
  }
docs: // NewTracker creates a memory tracker.
  //	1. "label" is the label used in the usage string.
  //	2. "bytesLimit < 0" means no limit.