code: func (r *ChtRequest) Request(reqID uint64, peer *peer) error {
  	peer.Log().Debug("Requesting CHT", "cht", r.ChtNum, "block", r.BlockNum)
  	var encNum [8]byte
  	binary.BigEndian.PutUint64(encNum[:], r.BlockNum)
  	req := HelperTrieReq{
  		Type:    htCanonical,
  		TrieIdx: r.ChtNum,
  		Key:     encNum[:],
  		AuxReq:  auxHeader,
  	}
  	return peer.RequestHelperTrieProofs(reqID, r.GetCost(peer), []HelperTrieReq{req})
  }
docs: // Request sends an ODR request to the LES network (implementation of LesOdrRequest)