code: func (r *responseStats) reset() {
  	r.totalCount += r.count
  	for code, count := range r.statusCodes {
  		r.totalStatusCodes[code] += count
  	}
  	r.count = 0
  	r.statusCodes = make(map[int]int)
  	r.bodies = make(map[string]int)
  	r.errors = make(map[string]int)
  	r.maxDuration = 0
  	r.sumDuration = 0
  	r.minDuration = 0
  }
docs: // reset the counters to zero.
  // NOT thread safe