code: public ServiceFuture<List<SecretItem>> getSecretVersionsAsync(final String vaultBaseUrl, final String secretName, final Integer maxresults, final ListOperationCallback<SecretItem> serviceCallback) {
          return AzureServiceFuture.fromPageResponse(
              getSecretVersionsSinglePageAsync(vaultBaseUrl, secretName, maxresults),
              new Func1<String, Observable<ServiceResponse<Page<SecretItem>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<SecretItem>>> call(String nextPageLink) {
                      return getSecretVersionsNextSinglePageAsync(nextPageLink);
                  }
              },
              serviceCallback);
      }
docs: List all versions of the specified secret.
  The full secret identifier and attributes are provided in the response. No values are returned for the secrets. This operations requires the secrets/list permission.
  
  @param vaultBaseUrl The vault name, for example https://myvault.vault.azure.net.
  @param secretName The name of the secret.
  @param maxresults Maximum number of results to return in a page. If not specified, the service will return up to 25 results.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object