func isRequestUnsignedTrailerV4(r *http.Request) bool {
	return r.Header.Get(xhttp.AmzContentSha256) == unsignedPayloadTrailer &&
		r.Method == http.MethodPut && strings.Contains(r.Header.Get(xhttp.ContentEncoding), streamingContentEncoding)
}

// Authorization type.
//
//go:generate stringer -type=authType -trimprefix=authType $GOFILE
type authType int