if ok {
				m[key] = strings.Join(value, ",")
				break
			}
		}
	}
	return nil
}

// Returns access credentials in the request Authorization header.
func getReqAccessCred(r *http.Request, region string) (cred auth.Credentials) {
	cred, _, _ = getReqAccessKeyV4(r, region, serviceS3)
	if cred.AccessKey == "" {
		cred, _, _ = getReqAccessKeyV2(r)
	}
	return cred
}