Subclass for asynchronous random search tuning.
This Tuner can be instantiated with the associated sugar function tnr():
tnr("async_random_search")
mlr3tuning::Tuner -> mlr3tuning::TunerAsync -> mlr3tuning::TunerAsyncFromOptimizerAsync -> TunerAsyncRandomSearch
The random points are sampled by paradox::generate_design_random().
Other TunerAsync:
mlr_tuners_async_design_points,
mlr_tuners_async_grid_search