FCollection View vs unmodifiable vs Immutable Refactor

Currently the FCollection View sits in the FCollection Class and doesn't implement either java Collection or java List
so each time we get a View and want to iterate over it in a different way, or want to get the size/empty check we need to cast to List or make a new Array List?

small steps:

- Make View implement List and Collection class, but make them fail on change, maybe implement them as Immutable List?
- Also use Immutable for EmptyFCollection ?
- Maybe add an Interface for FCollection that has all the methods (including the Modifying ones) and have View and Empty Collection use that Interface
- Implement FCollection as [ForwardingList](https://guava.dev/releases/snapshot/api/docs/com/google/common/collect/ForwardingList.html), + some Set Functions then it should be more easy to put a Immutable List inside for Empty?
- Or implement it as [SetUniqueList](https://commons.apache.org/proper/commons-collections/javadocs/api-3.2.2/index.html?org/apache/commons/collections/list/SetUniqueList.html) / [SetUniqueList](https://commons.apache.org/proper/commons-collections/apidocs/org/apache/commons/collections4/list/SetUniqueList.html)