code: func NewCustomTimer(h Histogram, m Meter) Timer {
  	if !Enabled {
  		return NilTimer{}
  	}
  	return &StandardTimer{
  		histogram: h,
  		meter:     m,
  	}
  }
docs: // NewCustomTimer constructs a new StandardTimer from a Histogram and a Meter.
  // Be sure to call Stop() once the timer is of no use to allow for garbage collection.