set
Call to define your user selection "sub-OpModes". If you list any, then the user will be prompted to select from these options during initialisation asynchronously. If you return null or don't call this method, then the user will not be prompted for a selection, and the OpMode will move to task-ready state immediately.
Review the UserSelection class and wiki documentation for more information regarding this feature, including chaining and what to expect regarding the runtime of this class.
By setting OpModes here, the onReady parameter will be of type T and you can cast it without needing to check.