Lenient HTTP version parsing

Invalid HTTP version (lenient)

GET / HTTP/5.6

off=0 message begin
off=0 len=3 span[method]="GET"
off=3 method complete
off=4 len=1 span[url]="/"
off=6 url complete
off=6 len=4 span[protocol]="HTTP"
off=10 protocol complete
off=11 len=3 span[version]="5.6"
off=14 version complete
off=18 headers complete method=1 v=5/6 flags=0 content_length=0
off=18 message complete