This widget automatically displays the progress of a lengthy download
operation. The widget itself ( i.e. the UI ) polls the specified file and
automatically updates the display as required even if the download is taking
place in the foreground.
Please notice that this will work only if the UI runs on the same machine as
the file to download which may not taken for granted ( but which is so for
most users ).
Note:
This is a "special" widget, i.e. not all UIs necessarily support it. Check
for availability with HasSpecialWidget( `DownloadProgress ) before using it.