proc init(T: type LookupState; targetId: Key; initialPeers: seq[PeerId];
          alpha: int; replication: int; hasher: Opt[XorDHasher]): T:type

proc markFailed(state: var LookupState; peerId: PeerId) {....raises: [], tags: [],
    forbids: [].}

proc markPending(state: var LookupState; peerId: PeerId) {....raises: [], tags: [],
    forbids: [].}

proc selectAlphaPeers(state: LookupState): seq[PeerId] {....raises: [], tags: [],
    forbids: [].}

proc selectClosestK(state: LookupState): seq[PeerId] {....raises: [], tags: [],
    forbids: [].}

proc updateShortlist(state: var LookupState; msg: Message;
                     onInsert: proc (p: PeerInfo) {....gcsafe, raises: [].};
                     hasher: Opt[XorDHasher]) {....raises: [], tags: [RootEffect],
    forbids: [].}