Specialized hashtable which can store multiple values for a given key. All values are stored in an UniqueValueList as value. When the value is requested, the UniqueValueList is returned, not the actual value.

[SerializableAttribute]
public class MultiValueHashtable<TKey, TValue> : Dictionary<TKey, UniqueValueList<TValue>>

<SerializableAttribute>
Public Class MultiValueHashtable(Of TKey, TValue)
	Inherits Dictionary(Of TKey, UniqueValueList(Of TValue))