          *     trace(c);
          *     //true
          * </pre>
+         * @internal immutable
          */
         public function some(callback:Function):Boolean
         {

         *     trace(s);
         *     //Stream{1, 1, 1}
         * </pre>
         */
        public function fill(value:*, length:int = -1):Stream
        {

         *     trace(s.pop());
         *     //3
         * </pre>
         * @internal mutable
         */
        public function pop():*
        {
