private static OpenSSLServerSocketFactoryImpl toConscrypt(SSLServerSocketFactory factory) {
        if (!isConscrypt(factory)) {
            throw new IllegalArgumentException(
                    "Not a conscrypt server socket factory: " + factory.getClass().getName());
        }
        return (OpenSSLServerSocketFactoryImpl) factory;
    }
Indicates whether the given {@link SSLServerSocketFactory} was created by this distribution
of Conscrypt.
common/src/main/java/org/conscrypt/Conscrypt.java