text: module.exports = ByteCounter;
  
  var Writable = require('readable-stream').Writable;
  var util = require('util');
  
  util.inherits(ByteCounter, Writable);
  function ByteCounter(options) {
    Writable.call(this, options);
    this.bytes = 0;
  }
  
  ByteCounter.prototype._write = function(chunk, encoding, cb) {
    this.bytes += chunk.length;
    this.emit('progress');
    cb();
  };
  