defaultSha256Cksum = emptySHA256
		v, ok = r.Header[xhttp.AmzContentSha256]
	}

	// We found 'X-Amz-Content-Sha256' return the captured value.
	if ok {
		return v[0]
	}

	// We couldn't find 'X-Amz-Content-Sha256'.
	return defaultSha256Cksum
}

// isValidRegion - verify if incoming region value is valid with configured Region.
func isValidRegion(reqRegion string, confRegion string) bool {