What do the numbers in rsync's output mean?

Question

When I run rsync with the --progress flag, I get information about the transfers as follows.

path/to/file           16 100%    0.01kB/s    0:00:01 (xfer#10857, to-check=427700/441502) 

What do the numbers in the second row mean? I know what some of them are, but what do the others mean (marked with ??? below)?

16 ???

100% amount of transfer completed in this file

0.0.1kB/s speed of current file transfer

0:00:01: time elapsed in current file transfer

10857 count of files transferred

427700 ???

441502 ???

Answer 1

When the file transfer finishes, rsync replaces the progress line with a summary line that looks like this:

 1238099 100%  146.38kB/s    0:00:08  (xfer#5, to-check=169/396) 

In this example, the file was 1238099 bytes long in total, the average rate of transfer for the whole file was 146.38 kilobytes per second over the 8 seconds that it took to complete, it was the 5th transfer of a regular file during the current rsync session, and there are 169 more files for the receiver to check (to see if they are up-to-date or not) remaining out of the 396 total files in the file-list.

from http://samba.anu.edu.au/ftp/rsync/rsync.html under --progress switch