code: func (sg *SampleGroup) AddSample(e *Sample) {
  	sg.Samples = append(sg.Samples, e)
  
  	if len(sg.Samples) == 1 {
  		sg.Start = e.Start
  		sg.End = e.End
  	}
  	sg.IOBytes += e.IOBytes
  	sg.JobMsgCnt += e.JobMsgCnt
  	sg.MsgCnt += e.MsgCnt
  	sg.MsgBytes += e.MsgBytes
  
  	if e.Start.Before(sg.Start) {
  		sg.Start = e.Start
  	}
  
  	if e.End.After(sg.End) {
  		sg.End = e.End
  	}
  }
docs: // AddSample adds a Sample to the SampleGroup. After adding a Sample it shouldn't be modified.