type t;
let findOpt: Peer.Id.t => t => option(Peer.t);findOpt(id, p) tries to find a peer with the specified id. Returns None if not found.
let fold: ('acc => Peer.t => 'acc) => 'acc => t => 'acc;fold(f, acc, t) can be used to iterate through all peers and accumulate a value with a starting value of acc.