code: function pollUntilDone(id, done) {
    client.droplets.get(id, function(err, droplet) {
      if (!err && droplet.locked === false) {
        // we're done!
        done.call();
      } else if (!err && droplet.locked === true) {
        // back off 10s more
        setTimeout(function() {
          pollUntilDone(id, done);
        }, (10 * 1000));
      } else {
        pollUntilDone(id, done);
      }
    });
  }
docs: Poll for non-locked state every 10s