uglyBis.js

;(function(){
  
  var foo = synchronousRequestInit
    , bar = synchronousRequestInit
    , fooResponse
    , barResponse
    , i = false
    , interval
  
  window.setTimeout(function(){
    fooResponse = foo.update()
    barResponse = bar.update()
    i = true
  }, 0)
  
  interval = window.setInterval(function(){
    if(!i) return
    else {
      callback(fooResponse, barResponse)
      window.clearInterval(interval)
    }
  }, 30)
})()