Adding better implementation note

daggy/include/daggy/ThreadPool.hpp

@@ -8,6 +8,14 @@
 #include <future>
 #include <deque>
 
+/*
+TODO: There's probably a better implementation of this at
+
+      https://github.com/vit-vit/CTPL/blob/master/ctpl_stl.h
+
+      but for now assume that all work is done using closures.
+*/
+
 namespace daggy {
   using AsyncTask = std::function<void()>;
   class ThreadPool {