BeginWaitCursor()
Displays the cursor as an hourglass. This can be used when you expect a
command to take a noticeable time to execute (eg, when a document
loads or saves itself to a file.).
The actions of BeginWaitCursor are not always effective outside of a single
message handler as other actions, such as OnSetCursor handling, could change
the cursor.
Call EndWaitCursor to restore the previous cursor.