private Selector createSelector(Map<String, Object> sslClientConfigs, final Integer netReadBufSize,
                                final Integer netWriteBufSize, final Integer appBufSize) {
        TestSslChannelBuilder channelBuilder = new TestSslChannelBuilder(ConnectionMode.CLIENT);
        channelBuilder.configureBufferSizes(netReadBufSize, netWriteBufSize, appBufSize);
        channelBuilder.configure(sslClientConfigs);
        if (this.selector != null) {
            this.selector.close();
        }
        this.selector = new Selector(100 * 5000, new Metrics(), TIME, "MetricGroup", channelBuilder, new LogContext());
        return selector;
    }
Tests invalid ssl.engine.factory plugin class
clients/src/test/java/org/apache/kafka/common/network/SslTransportLayerTest.java