POST / HTTP/1.1
Host:foo-service.foo-region.amazonaws.com
X-Amz-Date:20150830T123600Z
Authorization: AWS4-HMAC-SHA256 Credential=foo-akid/20150830/foo-region/foo-service/aws4_request, SignedHeaders=host;x-amz-date, Signature=8b264695a2fd7fe28b309c611e0770da5a4c5ca0c040209941f78d773d9297b2