Update ToDo.md

C#/AutoHotInterception/ToDo.md

@@ -13,3 +13,11 @@ Implement better system:
 
 Del is a good example:
 If Del (Above arrow keys, not on Numpad) is pressed while NumLock is off, it sends an Extended LCtrl, then the Pause Key
+
+# Send before firing callback in Subscription Mode?
+If trying to write a system like AHK's hotstrings, but using AHI, 
+if you had subscriptions with block set to false, you would want the key to be sent before firing the callback. 
+That way, if you intended to replace `btw` with `By the way`, when the callback fired for `w`, 
+the `w` would already be in the text editor.  
+As it stands, when the callback for `w` fired, the `w` would not bein the text editor, and after AHI sent the `w` 
+(After firing the callback), you would have no chance to delete the `w` (So you would end up with `by the wayw` in the text editor)