title: What's the use of 'Buffer.isBuffer' when you could use 'instanceof'?
body: <p>I don't understand what is the purpose of the <code>Buffer.isBuffer</code> function when <code>instanceof</code> works like a charm :</p>
  
  <pre><code>var b = new Buffer('blabla')
  assert.ok(b instanceof Buffer)
  </code></pre>