code: func (l *rateLimiterImpl) SetMaxQuota(q float64) error {
  	if q < 0 {
  		return errors.Newf("Max quota must be non-negative: %f", q)
  	}
  
  	l.mutex.Lock()
  	defer l.mutex.Unlock()
  
  	l.maxQuota = q
  	if l.quota > q {
  		l.quota = q
  	}
  
  	if l.maxQuota == 0 {
  		l.cond.Broadcast()
  	}
  
  	return nil
  }
docs: // This sets the leaky bucket's maximum capacity.  The value must be
  // non-negative.