code: public ServiceFuture<IssuerBundle> getCertificateIssuerAsync(String vaultBaseUrl, String issuerName, final ServiceCallback<IssuerBundle> serviceCallback) {
          return ServiceFuture.fromResponse(getCertificateIssuerWithServiceResponseAsync(vaultBaseUrl, issuerName), serviceCallback);
      }
docs: Lists the specified certificate issuer.
  The GetCertificateIssuer operation returns the specified certificate issuer resources in the specified key vault. This operation requires the certificates/manageissuers/getissuers permission.
  
  @param vaultBaseUrl The vault name, for example https://myvault.vault.azure.net.
  @param issuerName The name of the issuer.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object