public static int IndexOf<T>(
	this IEnumerable<T> source,
	Func<T, bool> predicate
)

<ExtensionAttribute>
Public Shared Function IndexOf(Of T) ( 
	source As IEnumerable(Of T),
	predicate As Func(Of T, Boolean)
) As Integer

public:
[ExtensionAttribute]
generic<typename T>
static int IndexOf(
	IEnumerable<T>^ source, 
	Func<T, bool>^ predicate
)

[<ExtensionAttribute>]
static member IndexOf : 
        source : IEnumerable<'T> * 
        predicate : Func<'T, bool> -> int