- * Implementations are advised to use the Externalizable Proxy pattern to
- * allow future evolution of their serialization format.
+ * Implementations are advised to use the {@link java.io.Externalizable} Proxy pattern to allow future evolution
+ * of their serialization format. For further efficiency, implementation should implement {@link WritableObject},
+ * so they can be efficiently embedded in other {@link Serializable} objects.
+ *
+ * Note that this class is annotated as {@link ThreadSafe}, hence all implementations are expected to be thread-safe.