text: 
  var throttle = require('./');
  
  function onprogress(n) {
    console.log('progress %s%', n);
  }
  
  onprogress = throttle(onprogress, 500);
  
  var n = 0;
  setInterval(function(){
    if (n >= 100) return;
    onprogress(n++);
  }, 50);
  