XEnumerableDistinctByTSource, TKey Method

public static IEnumerable<TSource> DistinctBy<TSource, TKey>(
	this IEnumerable<TSource> source,
	Func<TSource, TKey> keySelector,
	IEqualityComparer<TKey>? keyComparer = null
)

<ExtensionAttribute>
Public Shared Function DistinctBy(Of TSource, TKey) ( 
	source As IEnumerable(Of TSource),
	keySelector As Func(Of TSource, TKey),
	Optional keyComparer As IEqualityComparer(Of TKey) = Nothing
) As IEnumerable(Of TSource)

[<ExtensionAttribute>]
static member DistinctBy : 
        source : IEnumerable<'TSource> * 
        keySelector : Func<'TSource, 'TKey> * 
        ?keyComparer : IEqualityComparer<'TKey> 
(* Defaults:
        let _keyComparer = defaultArg keyComparer null
*)
-> IEnumerable<'TSource>