code: @Reference(service = ScheduledExecutorService.class, target = "(deferrable=false)")
      protected void setScheduledExecutorService(ScheduledExecutorService scheduler) {
          scheduledExecutorService.getAndSet(scheduler);
      }
docs: Inject a ServiceReference for the required/dynamic ScheduledExecutorService. If the service is different than the
  previous value, we need to queue established monitors to cancel their tasks with the old executor service, and
  reschedule them with the new one.
  
  @param schedulerRef
  ServiceReference for the required/dynamic ScheduledExcecutorService