Asynch Threading

[news.microsoft.com]

With WebServices in 2.0 where the proxy classes is created to allow you to
make a WebMethod call Asynch, when the delegate is called does it execute
on the background thread or the foreground thread? In other words in the
example below, will the wsWebServiceProxy_SendMessageCompleted be executed
on the same thread as the Foo() method?

Is there any need to unhook the EventHandler once the delegate has finished
executed *or* will the gc clean it up *or* does it depend on if the
wsWebServiceProxy's scope (i.e. if it's a local to the Foo() method or
global to the class?

private void Foo()
{
wsWebServiceProxy.SendMessageCompleted += new
SendMessageCompletedEventHandler(wsWebServiceProxy _SendMessageCompleted);
wsWebServiceProxy.SendMessageAsync(oMessage);
}

private void wsWebServiceProxy_SendMessageCompleted(object sender,
SendMessageEventArgs e)
{
//Execute any code after the WebMethod call has completed
//Does code executed here need to be Invoked to execute on the
foreground thread?

//Is this needed or does this depend on the scope of the
wsWebServiceProxy object?
((WebServiceProxy)sender).SendMessageCompleted -= new
SendMessageCompletedEventHandler(wsWebServiceProxy _SendMessageCompleted);
}

TIA