@Test void ip_ipv6_compatIpv4() {
    String ipv6 = "::0000:43.0.192.2";
    Endpoint endpoint = Endpoint.newBuilder().ip(ipv6).build();

    assertExpectedIpv4(endpoint);
  }
Many getPort operations return -1 by default. Leniently coerse to null.
zipkin/src/test/java/zipkin2/EndpointTest.java