code: func SignV2(req *request.Request) {
  	// If the request does not need to be signed ignore the signing of the
  	// request if the AnonymousCredentials object is used.
  	if req.Config.Credentials == credentials.AnonymousCredentials {
  		return
  	}
  
  	v2 := signer{
  		Request:     req.HTTPRequest,
  		Time:        req.Time,
  		Credentials: req.Config.Credentials,
  		Debug:       req.Config.LogLevel.Value(),
  		Logger:      req.Config.Logger,
  		pathStyle:   aws.BoolValue(req.Config.S3ForcePathStyle),
  	}
  
  	req.Error = v2.Sign()
  }
docs: // Sign requests with signature version 2.
  //
  // Will sign the requests with the service config's Credentials object
  // Signing is skipped if the credentials is the credentials.AnonymousCredentials
  // object.