// https://developers.google.com/web/updates/2012/06/How-to-convert-ArrayBuffer-to-and-from-String
const unpack = (packed) => {
  const string = window.atob(packed)
  const buffer = new ArrayBuffer(string.length)
  const bufferView = new Uint8Array(buffer)
  
  for (let i = 0; i < string.length; i++) {
    bufferView[i] = string.charCodeAt(i)
  }
  
  return buffer
}