code: func (l *StructLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error {
  	l.output = output
  	l.err = err
  	if l.cfg.Debug {
  		fmt.Printf("0x%x\n", output)
  		if err != nil {
  			fmt.Printf(" error: %v\n", err)
  		}
  	}
  	return nil
  }
docs: // CaptureEnd is called after the call finishes to finalize the tracing.