zlibs gzip dosent work with http

[Sean Campbell via Digitalmars-d-learn]

I'm trying to add gzip compression to a HTTP server i wrote in D. 
here is the code that dose the gzip encoding.

if ((Info.modGzip) & 
(indexOf(client.getRequestHeaderFieldValue("Accept-Encoding"),"gzip") 
!= -1)){
	writeln("gzip");
	auto gzip = new Compress(HeaderFormat.gzip);
	client.addToResponseHeader("Content-Encoding: gzip");
	client.sendHeader("200 ok");
	while (0 < (filestream.readBlock(readbuffer))){
		client.client.send(gzip.compress(readbuffer));
	}
	client.client.send(gzip.flush());
	delete gzip;
	delete filestream;
}

but when i test it Firefox, internet explorer and chrome says 
that the encoding or compression is bad. why? the data is 
compressed with gzip.

the rest of the code is available at 
http://sourceforge.net/p/netspark/netsparkb1/ci/master/tree/

Git
git clone git://git.code.sf.net/p/netspark/netsparkb1 
netspark-netsparkb1