code: func (q *queue) ReserveReceipts(p *peerConnection, count int) (*fetchRequest, bool, error) {
  	isNoop := func(header *types.Header) bool {
  		return header.ReceiptHash == types.EmptyRootHash
  	}
  	q.lock.Lock()
  	defer q.lock.Unlock()
  
  	return q.reserveHeaders(p, count, q.receiptTaskPool, q.receiptTaskQueue, q.receiptPendPool, q.receiptDonePool, isNoop)
  }
docs: // ReserveReceipts reserves a set of receipt fetches for the given peer, skipping
  // any previously failed downloads. Beside the next batch of needed fetches, it
  // also returns a flag whether empty receipts were queued requiring importing.