public SELF customizer(
            Consumer<? super CuratorFrameworkFactory.Builder> customizer) {
        ensureInternalClient();
        assert customizers != null;
        customizers.add(requireNonNull(customizer, "customizer"));
        return self();
    }
Specifies the {@link Consumer} that customizes the {@link CuratorFramework}.

@throws IllegalStateException if this builder was created with an existing {@link CuratorFramework}
                              instance.
zookeeper3/src/main/java/com/linecorp/armeria/common/zookeeper/AbstractCuratorFrameworkBuilder.java