code: func (r *Timing) Add(duration time.Duration) {
  	b := r.getCurrentBucket()
  
  	r.Mutex.Lock()
  	defer r.Mutex.Unlock()
  
  	b.Durations = append(b.Durations, duration)
  	r.removeOldBuckets()
  }
docs: // Add appends the time.Duration given to the current time bucket.