public override bool IsContextOK(Context ctx, IConstructionCallMessage msg)
 {
     SyncContext sctx = SyncContext.GetContext ();
     if (sctx == null || (sctx.GetType() != contextType)) {
         syncContext = (SyncContext) Activator.CreateInstance (contextType);
         return false;
     }
     else {
         syncContext = sctx;
         return true;
     }
 }
 public static void SetContext(SyncContext ctx)
 {
     context = ctx;
 }
 public SyncContextDispatchSink(IMessageSink nextSink, SyncContext syncContext)
 {
     this.nextSink = nextSink;
     this.syncContext = syncContext;
 }