code: public ServiceFuture<SecretBundle> getSecretAsync(String vaultBaseUrl, String secretName,
              final ServiceCallback<SecretBundle> serviceCallback) {
          return getSecretAsync(vaultBaseUrl, secretName, "", serviceCallback);
      }
docs: Get a specified secret from a given key vault.
  
  @param vaultBaseUrl
  The vault name, e.g. https://myvault.vault.azure.net
  @param secretName
  The name of the secret in the given vault
  @param serviceCallback
  the async ServiceCallback to handle successful and failed
  responses.
  @return the {@link ServiceFuture} object