private NioEchoServer createEchoServer(ListenerName listenerName, SecurityProtocol securityProtocol) throws Exception {
        return NetworkTestUtils.createEchoServer(listenerName, securityProtocol,
                new TestSecurityConfig(saslServerConfigs), credentialCache, time);
    }
Tests client connection close before response for authentication failure is sent.
clients/src/test/java/org/apache/kafka/common/security/authenticator/SaslAuthenticatorFailureDelayTest.java