public Optional<X509Certificate> getIssuer() {
    return Optional.ofNullable(issuer);
  }
Class which encapsulates a {@link X509Certificate} as well as the associated
{@link KeyPair}. If the certificate is not self-signed it will also hold an issuer.
<p>
{@code CertificateMaterial} is produced by {@link CertificateBuilder}s.

@see CertificateBuilder
@see CertStores
geode-junit/src/main/java/org/apache/geode/cache/ssl/CertificateMaterial.java