@Override
    public MetadataNode child(String name) {
        try {
            Integer brokerId = Integer.valueOf(name);
            ControllerRegistration registration = image.controllers().get(brokerId);
            if (registration == null) return null;
            return new MetadataLeafNode(registration.toString());
        } catch (NumberFormatException e) {
            return null;
        }
    }
@Test
    public void testNode1Child() {
        MetadataNode child = NODE.child("2");
        assertNotNull(child);
        assertEquals("ControllerRegistration(id=2, " +
            "incarnationId=adGo6sTPS0uJshjvdTUmqQ, " +
            "zkMigrationReady=false, " +
            "listeners=[], " +
            "supportedFeatures={metadata.version: 1-4})",
            child.stringify());
    }