title: Implementing background worker - Obj C/Cocoa
body: <p>I have 2 windows in my cocoa app. Main window opens a sub window. On click of OK on the sub window, I invoke a deligate on main form which will tell that OK button is clicked on the sub window.</p>
  
  <p>Now, I need to run a long running process on the main window "in the background" so that the window will not become unresponsive. I also have progress bar which should show progress of this long running process.</p>
  
  <p>Please let me know, what is the best way to achieve this.</p>