Support compression in the Endsley format.

While compression is normally handled by a higher level in the Endsley
format, this patch allows to optionally compress the patch here. This
helps estimate the size of the compressed Endsley patch which is what
ends up being transmitted.

Bug: 71854816
Test: Added unittests, ran it from the command line

Change-Id: I2bd068c62a7d6aa5b1c71c38dcfe45ef82b9c2f2