ion:
    Description:
     Macro. Build active progress bar. Requires size
     and description that will be printed out to
     the REPL. If *progress-bar-endabled* is nil or
     there is another progress bar active already
     progress bar will not be shown.
    
    Notes:
     Because with-progress-bar handles cases where
     another progress-bar is active it is generally
     safe to nest code with this macro on call stack.
     However, top level with-progress-bar should
     contain correct steps-