Why common-compress skip data by reading and discard?

Hello,

When I reading the code of common-compress, I found it skip data using 
the `IOUtils.skip` in `commons-io` module.

I found this method just reading the data and discard it directly. But 
in JDK there's an more effeciency method `InputStream.skip` and 
`InputStream.skipNBytes`.

So why we read & discard data instead of call `skip*` directly?

Thank you.

iseki zero.