public static IReadOnlyLookup<TKey, TValue> Empty<TKey, TValue>()
Public Shared Function Empty(Of TKey, TValue) As IReadOnlyLookup(Of TKey, TValue)
public:
generic<typename TKey, typename TValue>
static IReadOnlyLookup<TKey, TValue>^ Empty()
static member Empty : unit -> IReadOnlyLookup<'TKey, 'TValue>