code: func (l *JSONLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error {
  	log := StructLog{
  		Pc:            pc,
  		Op:            op,
  		Gas:           gas,
  		GasCost:       cost,
  		MemorySize:    memory.Len(),
  		Storage:       nil,
  		Depth:         depth,
  		RefundCounter: env.StateDB.GetRefund(),
  		Err:           err,
  	}
  	if !l.cfg.DisableMemory {
  		log.Memory = memory.Data()
  	}
  	if !l.cfg.DisableStack {
  		log.Stack = stack.Data()
  	}
  	return l.encoder.Encode(log)
  }
docs: // CaptureState outputs state information on the logger.