title: Differing Blob sizes before and after reading with FileReader
body: <p>I am trying to read a Blob withe Javascript FileReader API using the following code:</p>
  
  <pre><code>reader = new FileReader();
  reader.onloadend = function(evt) {
    console.log(new Blob([reader.result]));
  }
  // outBlob defined elsewhere
  console.log(outBlob);
  reader.readAsBinaryString(outBlob);
  </code></pre>
  
  <p>Running this in Chrome gives:</p>
  
  <pre><code>          Blob {type: "undefined", size: 70012, slice: function}
            Blob {type: "", size: 105244, slice: function}
  </code></pre>
  
  <p>My question is, why are the sizes different here? </p>