title: Use HTTP Keep-Alive for server to communicate to client
body: <p>Recently in an interview I was asked how I would approach an online chat client application.  I went through the standard "polling" solution but was cut off because the interviewer was looking for the "HTTP 1.1 keep-alive" method.  Having used HTTP for quite a while and remembering that the whole point was to be "stateless", this never occurred to me (also, not to mention that the keep-alive is not consistently implemented).</p>
  
  <p>My question is, is it possible for a web server to broadcast and/or send information to a client when the "keep-alive" header has been set?</p>