+ * <p>
+ * A {@link Progress} can have a name, and that name will be reported through
+ * the event system (it will report the first non-null name in the stack from
+ * the {@link Progress} from which the event originated to the parent the event
+ * is listened on).
+ * <p>
+ * The {@link Progress} also has a table of keys/values shared amongst all the
+ * hierarchy (note that when adding a {@link Progress} to others, its values
+ * will be prioritized if some with the same keys were already present in the
+ * hierarchy).