title: convert blob to arraybuffer without filereader/xmlttprequest
body: <p>I want to convert from ArrayBuffer (lets say 100MB) to Blob then back from Blob to ArrayBuffer without duplicating the data.<br>
  FileReader / XMLHttpRequest do duplicate the data, so is there an other way?  </p>
  
  <p><code>var b = new Blob([new Uint8Array(someArrayBuffer)]);</code></p>
  
  <p>PS: I want to make cross-tab communication of large  read only buffer without duplicating it, e.g. a local ArrayBuffer is 500MB I want to use it in multiple tabs without duplicating the data.</p>