Example of requesting gzip in HTTP request:
POST /api-v2/ HTTP/1.0
User-Agent: curl/7.19.7 (x86_64-pc-linux-gnu) libcurl/7.19.7 zlib/1.2.3
Host: api.travelfusion.com
Accept: */*
Accept-Encoding: gzip
Content-Type: text/xml; charset=utf-8
Content-Length: 174