Dim instance As IEndpointBase
Dim request As InvokeServiceMessage
Dim callback As AsyncCallback
Dim asyncState As Object
Dim value As IAsyncResult
 
value = instance.BeginInvokeService(request, callback, asyncState)

[OperationContractAttribute(Action="http://opcfoundation.org/UA/2008/02/Services.wsdl/InvokeService", 
   ReplyAction="http://opcfoundation.org/UA/2008/02/Services.wsdl/InvokeServiceResponse", 
   AsyncPattern=true)]
IAsyncResult BeginInvokeService( 
   InvokeServiceMessage request,
   AsyncCallback callback,
   object asyncState
)