title: How to implement a writable stream
body: <p>I want to pipe data from an amazon kinesis stream to a an s3 log or a bunyan log.</p>
  
  <p>The sample works with a file write stream or stdout.  How would I implmeny my own writable stream?</p>
  
  <pre><code>//this works
  var file = fs.createWriteStream('my.log')
  kinesisSource.pipe(file)
  </code></pre>
  
  <p>this doesn't work saying it has no method 'on'</p>
  
  <pre><code>var stream = {}; //process.stdout works however
  stream.writable = true;
  stream.write =function(data){
      console.log(data);
  };
  kinesisSource.pipe(stream);
  </code></pre>
  
  <p>what methods do I have to implement for my own custom writable stream, the docs seem to indicate I need to implement 'write' and not 'on'</p>