title: How do server-client push/pull connections work?
body: <p>I'm very interested in how financial data is streamed from server to client. I often here the term 'push-pull' used. I wondered if someone could give me an example (preferably in Java, C# or perhaps Javascript) how this is actually achieved? Whenever I have written amateur hobby projects at home I often end up querying a URL (containing the price) and continuously calling this within a while(true) loop, with a thread.sleep(x), even if the price doesnt change.</p>
  
  <p>Thanks in advance</p>