title: gulp.on('data') How to pass data to next pipe
body: <p>how to pass the data back from gulp.on('data') to the next step/pipe for eg. .pipe gulp.dest
  Here is a sample code in coffee</p>
  
  <pre><code>gulp.src(src)
      .on 'data',-&gt;
              # make change to file object
              # pass back the changed file object ?? how to pass it back to the next stream
      .pipe gulp.dest(dest)
  </code></pre>