func (l Link) Next(state State) Link { return Link{C.pn_link_next(l.pn, C.pn_state_t(state))} }
func (c Connection) SessionHead(s State) Session { return Session{C.pn_session_head(c.pn, C.pn_state_t(s))} }
func (s Session) Next(state State) Session { return Session{C.pn_session_next(s.pn, C.pn_state_t(state))} }
func (c Connection) LinkHead(s State) Link { return Link{C.pn_link_head(c.pn, C.pn_state_t(s))} }