@htoothrot mentioned at howeyc/fsnotify#56 (comment)

ReadDirectoryChanges[1] has a "bWatchSubtree" argument. If this argument is true, you will receive events for all files/directories for the whole directory tree rooted at the given directory.

As watching a large/busy tree can lead to many events I thought this was worth bringing up: It may be helpful to have the buffer size configurable in some way. Right now it's a hard coded 4096 bytes. When many events fire quickly, events can be dropped when the buffer is full. There are caveats to simply increasing the size (http://stackoverflow.com/a/3250454 explains some of the issues) and it seems there's not one answer to fit all uses.

Also look into FindFirstChangeNotification