Field-level annotation that indicates the objects referred to in the field are a child of the current entity. This
means events applied on the current instance are also propagated to the object contained in the field.
This annotation may be placed on any type of field. If the field holds a collection, array or map, applied events
are propagated to each individual item in the collection, array or map (both keys and values) that are instance of
EventSourcedEntity
.