@Override
    public String toString() {
        return toString(false);
    }
@Test
    public void testUnsupportedVersionsToString() {
        NodeApiVersions versions = new NodeApiVersions(new ApiVersionCollection(), Collections.emptyList(), false);
        StringBuilder bld = new StringBuilder();
        String prefix = "(";
        for (ApiKeys apiKey : ApiKeys.clientApis()) {
            bld.append(prefix).append(apiKey.name).
                    append("(").append(apiKey.id).append("): UNSUPPORTED");
            prefix = ", ";
        }
        bld.append(")");
        assertEquals(bld.toString(), versions.toString());
    }