More work on tangibleCharacter, especially thread synch stuff

Source/Integration/TriggeredTask.h

@@ -11,15 +11,13 @@
 // * You have a function to run in the background.
 // * It should start the instant a foreground thread says "NOW".
 // * It should be run exactly once for each "NOW".
+// * The foreground thread eventually waits for the background thread to finish.
 //
 // To use this class, construct an FTriggeredTask,
 // and provide a runnable object.  The runnable
 // object's "Run" method will get executed in
 // each time you call 'Trigger' on the FTriggeredTask.
 //
-// The run method will never get called reentrantly,
-// even if you call 'Trigger' rapidly in succession.
-//
 ///////////////////////////////////////////////
 
 class FTriggeredTask : public FRunnable
@@ -43,7 +41,12 @@ private:
 	// once. But if ThreadStopRequested is true, it means we
 	// want the thread to exit.
 	//
-	FEvent* ThreadEvent;
+	FEvent* CallEvent;
+
+	// This event is used when the thread is done
+	// with its work.
+	//
+	FEvent* ReturnEvent;
 
 	// The client whose task we're triggering.
 	//
@@ -91,12 +94,18 @@ public:
 	// Trigger
 	//
 	// Run the client's 'RUN' method once, in the
-	// background.  Trigger is a no-op if the system
-	// is shut down.  If you trigger when the task
-	// is already running, a trigger may get dropped.
+	// background.
 	//
 	void Trigger();
 
+	// Wait
+	//
+	// Wait for the background task to finish its work.
+	// If the background thread isn't running, then this
+	// returns immediately.
+	//
+	void Wait();
+
 	// IsRunning
 	//
 	bool IsRunning();