title: svn resuming aborted checkout
body: <p>Situation - have enormous repository, slow and unreliable link (read - vpn that breaks from time to time).</p>
  
  <p>We are subject of frequent branching, moving things, so every now and then whole new branch should be taken from the repository (checkout).</p>
  
  <p>Is there a way to 'resume' broken checkouts?  Is it safe to do <code>svn checkout</code> with same parameters and expect it to skip what is downloaded and download what is not?</p>