--- a/Implab/TaskController.cs	Wed Sep 03 18:34:02 2014 +0400
+++ b/Implab/TaskController.cs	Fri Apr 22 13:10:34 2016 +0300
@@ -92,14 +92,17 @@
             }
         }
 
-        public bool Cancel() {
+        public void Cancel() {
             lock (m_lock) {
-                if (!m_cancelled) {
+                if (!m_cancelled)
                     m_cancelled = true;
-                    return true;
-                } else {
-                    return false;
-                }
+            }
+        }
+
+        public void Cancel(Exception reason) {
+            lock (m_lock) {
+                if (!m_cancelled)
+                    m_cancelled = true;
             }
         }