in Sources/OSS/Signer/SignerV4.swift [89:93]
func postAuthHeader(request: inout RequestMessage, context: inout SigningContext, signature: String) {
let credential = "OSS4-HMAC-SHA256 Credential=\(context.credentials!.accessKeyId)/\(context.scopeToSign)"
let signedHeaders = context.additionalHeadersToSign == "" ? "" : ",AdditionalHeaders=\(context.additionalHeadersToSign)"
request.headers["Authorization"] = "\(credential)\(signedHeaders),Signature=\(signature)"
}