title: socket.io sync state across sockets
body: <p>I'm creating a board game where 2 players can play, and others can be spectators (viewers)
  so, when a spectator joins, he gets the current state of the game, and from then on, he only gets the move each player has made (to save data obviously). </p>
  
  <p><strong>My question is</strong>: when the spectator first get the state of the game from the server, how can I make sure it is actually synced? I don't really know <em>when</em> he will get the state, and it might be a fraction of a second <em>before</em> something has changed, and then the Delta he gets for every move made won't make sense.</p>
  
  <p>Should I use some kind of an internal? what would you suggest to make sure everything is synced?</p>