mvvmfx/src/main/java/de/saxsys/mvvmfx/utils/mapping/ModelWrapper.java
private static <T> ObservableSet<T> observableHashSet(Set<T> source) {
		return FXCollections.observableSet(new HashSet<>(source));
	}
private static <T> ObservableSet<T> observableHashSet(Set<T> source) {
		return FXCollections.observableSet(new HashSet<>(source));
	}
This helper method is needed because there is no equivalent of {@link FXCollections#observableArrayList(Collection)}
for {@link Set}.
The only factory method available for sets is {@link FXCollections#observableSet(Set)} which creates an observable set
that is backed by the given set. However, this would mean that changes to the observable set are directly synchronized back to the
source set. In contrast to this {@link FXCollections#observableArrayList(Collection)} creates an observable list that has
initially all values of the source list but changes aren't synchronized back because internally a new ArrayList is created.
We need exactly this behaviour for Sets and therefore are using this helper method.