Public Overloads Overridable Function Contains( _
   ByVal subscriber As Action(Of TPayload) _
) As Boolean

Dim instance As DelegateEvent(Of TPayload)
Dim subscriber As Action(Of TPayload)
Dim value As Boolean
 
value = instance.Contains(subscriber)

public virtual bool Contains( 
   Action<TPayload> subscriber
)

public function Contains( 
    subscriber: Action
): Boolean; virtual; 

public function Contains( 
   subscriber : Action
) : boolean;

public: virtual bool Contains( 
   Action<TPayload*>* subscriber
) 

public:
virtual bool Contains( 
   Action<TPayload^>^ subscriber
)