Super-simple profiler for async operations

simple_async_profile.js

function _test(cb) {
  var file_line = new Error().stack.split(/\n/g)[2].trim();
  var start = Date.now();
  return function () {
    console.log("%d :: %s", (Date.now() - start)/1000, file_line);
    cb.apply(null, arguments);
  }
}