code: function (sessionKey) {
          //The first 16 bytes (MSB first) will be the key, the next 16 bytes (MSB first) will be the initialization vector (IV), and the final 8 bytes (MSB first) will be the salt.
          var key = new Buffer(16); //just the key... +8); //key plus salt
          var iv = new Buffer(16); //initialization vector
  
          sessionKey.copy(key, 0, 0, 16); //copy the key
          sessionKey.copy(iv, 0, 16, 32); //copy the iv
  
          return new CryptoStream({
              key: key,
              iv: iv,
              encrypt: false
          });
      }
docs: Returns a readable/writeable aes 128 cbc stream for communicating
  with the spark core
  @param sessionKey
  @returns {*}
  @constructor