One common scheduler in RxJS is the observeOn() operator. The observeOn() operator is used to specify the scheduler on which an observable should emit its values.

In this example, the from() function is used to create an observable that emits the values 1, 2, and 3. The observeOn() operator is then used to specify that the observable should emit its values on the async scheduler, which will cause the values to be emitted asynchronously. The asyncScheduler is a common scheduler in RxJS that schedules tasks to be executed asynchronously using setTimeout().