I suppose he refers to this... \* IO * extended methods: * IO#seek supports SEEK...

I suppose he refers to this...

* IO

  * extended methods:

    * IO#seek supports SEEK_DATA and SEEK_HOLE as whence.

    * IO#seek accepts symbols (:CUR, :END, :SET, :DATA, :HOLE) for 2nd argument.

    * IO#read_nonblock accepts optional `exception: false` to return symbols

    * IO#write_nonblock accepts optional `exception: false` to return symbols

see https://github.com/ruby/ruby/blob/v2_1_0_preview1/NEWS