code: public Observable<CheckAvailabilityResourceInner> checkAvailabilityAsync(CheckAvailabilityParameters parameters) {
          return checkAvailabilityWithServiceResponseAsync(parameters).map(new Func1<ServiceResponse<CheckAvailabilityResourceInner>, CheckAvailabilityResourceInner>() {
              @Override
              public CheckAvailabilityResourceInner call(ServiceResponse<CheckAvailabilityResourceInner> response) {
                  return response.body();
              }
          });
      }
docs: Checks the availability of the given service namespace across all Windows Azure subscriptions. This is useful because the domain name is created based on the service namespace name.
  
  @param parameters The namespace name.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the CheckAvailabilityResourceInner object