paxos_protocol::status preparereq(prepareres & r, const node_t & src, unsigned instance, prop_t n);
paxos_protocol::status acceptreq(bool & r, const node_t & src, unsigned instance, prop_t n, const value_t & v);
paxos_protocol::status preparereq(prepareres & r, const node_t & src, unsigned instance, prop_t n);
paxos_protocol::status acceptreq(bool & r, const node_t & src, unsigned instance, prop_t n, const value_t & v);