public static T WithExtension<T>(
	this ActorSystem system
)
where T : class, IExtension

<ExtensionAttribute>
Public Shared Function WithExtension(Of T As {Class, IExtension}) ( 
	system As ActorSystem
) As T

public:
[ExtensionAttribute]
generic<typename T>
where T : ref class, IExtension
static T WithExtension(
	ActorSystem^ system
)

[<ExtensionAttribute>]
static member WithExtension : 
        system : ActorSystem -> 'T  when 'T : not struct and IExtension