public static synchronized int getAvailablePort() {
        int randomPort = getRandomPort();
        return getAvailablePort(randomPort);
    }
@Test
    void testGetAvailablePort() {
        assertThat(NetUtils.getAvailablePort(), greaterThan(0));
        assertThat(NetUtils.getAvailablePort(12345), greaterThanOrEqualTo(12345));
        assertThat(NetUtils.getAvailablePort(-1), greaterThanOrEqualTo(0));
    }