+In an incremental recursion scan, rsync won't know the total number of files
+in the file-list until it reaches the ends of the scan, but since it starts to
+transfer files during the scan, it will display a line with the text "ir-chk"
+(for incremental recursion check) instead of "to-chk" until the point that it
+knows the full size of the list, at which point it will switch to using
+"to-chk". Thus, seeing "ir-chk" lets you know that the total count of files
+in the file list is still going to increase (and each time it does, the count
+of files left to check will increase by the number of the files added to the
+list).
+