code: function queueLocation(ctx, next) {
    if (ctx.err) return next(ctx.err);
  
    try {
      // Get queue number from location header
      var parts = ctx.res.headers.location.split('/');
  
      return next(false, null, parseInt(parts[parts.length - 2], 10));
    } catch (err) {
      // ignore errors
    }
  
    next();
  }
docs: Queue location