[Streaming] Datum compression

Hello,

I think about following functionality to add to streaming. In some way earlier
or later soemone will add possibility for gzip communication. As I try to make
streaming, I wonder if it is possible to change TOAST compression to
GZIP/zLib, currently is LZMA.

I want to make this: if user want to use compression during communication,
server will be able to send compressed datum, instead of doing recompression.
GZIP is actually quite popular, and skipping "plain" Windows C, it's supported
on all driver platforms, including Java and .NET.

What do You think about this approach.

Regards,
Radek.