code: public Observable<Void> purgeDeletedStorageAccountAsync(String vaultBaseUrl, String storageAccountName) {
          return purgeDeletedStorageAccountWithServiceResponseAsync(vaultBaseUrl, storageAccountName).map(new Func1<ServiceResponse<Void>, Void>() {
              @Override
              public Void call(ServiceResponse<Void> response) {
                  return response.body();
              }
          });
      }
docs: Permanently deletes the specified storage account.
  The purge deleted storage account operation removes the secret permanently, without the possibility of recovery. This operation can only be performed on a soft-delete enabled vault. This operation requires the storage/purge permission.
  
  @param vaultBaseUrl The vault name, for example https://myvault.vault.azure.net.
  @param storageAccountName The name of the storage account.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceResponse} object if successful.