The meaning of the rsync to-check output

When using rsync transmission, some information is output, such as

146000/146067/20150310092532.apk
232123287 100% 5.66mb/s 0:00:39 (xfer#140, to-check=1008/2912)

In this example, the file size is 232123287 bytes, the average speed of transmission is 5.66mb/s, it takes 39 seconds to pass the file,

XFER#140 indicates that this is the 140th file of the current transmission,

To-check=1008/2912 said that there are currently 1008 remaining files are not checked, total is 2,912 need to check.

The meaning of the rsync to-check output