The Ironclad user (must be a user in your Ironclad account) to be used for launching the workflow. This is required when using a legacy bearer token but will be ignored when using an OAuth token. If the token was generated with the Authorization Code grant, the associated token user will be used. If the token was generated with the Client Credentials grant, the required x-as-user-id or x-as-user-email header will be used.