@UnstableApi
    public static TlsEngineType tlsEngineType() {
        if (tlsEngineType != null) {
            return tlsEngineType;
        }
        detectTlsEngineAndDumpOpenSslInfo();
        assert tlsEngineType != null;
        return tlsEngineType;
    }
Returns the {@link TlsEngineType} that will be used for processing TLS connections.

<p>The default value of this flag is {@link TlsEngineType#OPENSSL}.
Specify the {@code -Dcom.linecorp.armeria.tlsEngineType=<jdk|openssl>} JVM option to override
the default value.
core/src/main/java/com/linecorp/armeria/common/Flags.java