POST / http/1.1
Content-Type:application/x-www-form-urlencoded; charset=utf8
Date:Mon, 09 Sep 2011 23:36:00 GMT
Host:host.foo.com
Authorization: AWS4-HMAC-SHA256 Credential=AKIDEXAMPLE/20110909/us-east-1/host/aws4_request, SignedHeaders=content-type;date;host, Signature=b105eb10c6d318d2294de9d49dd8b031b55e3c3fe139f2e637da70511e9e7b71

foo=bar