code: func (s *SwarmChunkServer) SetNextBatch(_, _ uint64) (hashes []byte, from uint64, to uint64, proof *HandoverProof, err error) {
  	select {
  	case hashes = <-s.batchC:
  	case <-s.quit:
  		return
  	}
  
  	from = s.currentLen
  	s.currentLen += uint64(len(hashes))
  	to = s.currentLen
  	return
  }
docs: // SetNextBatch