code: public BackupSecretResult backupSecret(String vaultBaseUrl, String secretName) {
          return backupSecretWithServiceResponseAsync(vaultBaseUrl, secretName).toBlocking().single().body();
      }
docs: Backs up the specified secret.
  Requests that a backup of the specified secret be downloaded to the client. All versions of the secret will be downloaded. This operation requires the secrets/backup permission.
  
  @param vaultBaseUrl The vault name, for example https://myvault.vault.azure.net.
  @param secretName The name of the secret.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws KeyVaultErrorException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the BackupSecretResult object if successful.