The async property is available only for the following JSDO events or in the request object returned to a jQuery Promise callback:
afterCreate
afterDelete
afterFill
afterInvoke
afterUpdate
This request object property is also available for any session online and offline events that are fired in response to the associated resource operation when it encounters a change in the online status of the JSDO login session (JSDOSession or Session object). The request object is itself passed as a parameter to any event handler functions that you subscribe or register to JSDO events, any returned jQuery Promises, and to the online and offline events of the session that manages Data Object Services for the JSDO. This object is also returned as the value of any JSDO invocation method that you execute synchronously.