When you gunzip a streaming response, you can race on OA_GZIPBITS

gunzip_streaming.vtc

varnishtest "VDP gunzip OA_GZIPBITS streaming race"

# Note this should run with -j64 -n10000

server s1 -repeat 50 {
	rxreq
	txresp -gziplen 3167
} -start

varnish v1 -vcl+backend {
	sub vcl_recv {
		return (pass);
	}
} -start

client c1 -repeat 50 {
	txreq
	rxresp
	# 503 is an unrelated system error
	expect resp.status == 200
	# 3167 with a missing 8 bit write is either 3072 or 95
	# No Content-Length (chunked) is valid for this race
	expect resp.http.Content-Length != "3072"
	expect resp.http.Content-Length != "95"
	expect resp.bodylen == 3167
} -run