code: public ServiceFuture<Boolean> existsAsync(String jobScheduleId, final ServiceCallback<Boolean> serviceCallback) {
          return ServiceFuture.fromHeaderResponse(existsWithServiceResponseAsync(jobScheduleId), serviceCallback);
      }
docs: Checks the specified job schedule exists.
  
  @param jobScheduleId The ID of the job schedule which you want to check.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object