public static IEnumerable<TSource> Trace<TSource>(
	this IEnumerable<TSource> source,
	Func<TSource, string> formatter
)

<ExtensionAttribute> _
Public Shared Function Trace(Of TSource) ( _
	source As IEnumerable(Of TSource), _
	formatter As Func(Of TSource, String) _
) As IEnumerable(Of TSource)

public:
[ExtensionAttribute]
generic<typename TSource>
static IEnumerable<TSource>^ Trace(
	IEnumerable<TSource>^ source, 
	Func<TSource, String^>^ formatter
)