code: func (i *Inbox) AutoCash(cashInterval time.Duration, maxUncashed *big.Int) {
  	defer i.lock.Unlock()
  	i.lock.Lock()
  	i.maxUncashed = maxUncashed
  	i.autoCash(cashInterval)
  }
docs: // AutoCash (re)sets maximum time and amount which triggers cashing of the last uncashed
  // cheque if maxUncashed is set to 0, then autocash on receipt.