code: func (s *UniformSample) Snapshot() Sample {
  	s.mutex.Lock()
  	defer s.mutex.Unlock()
  	values := make([]int64, len(s.values))
  	copy(values, s.values)
  	return &SampleSnapshot{
  		count:  s.count,
  		values: values,
  	}
  }
docs: // Snapshot returns a read-only copy of the sample.