Comment 38 for bug 64067

From a distance, most problems look simpler than they are :-)

If you're interested in copying a single file, then maybe dd already provides
what you want? From dd --help:

Sending a USR1 signal to a running `dd' process makes it
print I/O statistics to standard error and then resume copying.

  $ dd if=/dev/zero of=/dev/null& pid=$!
  $ kill -USR1 $pid; sleep 1; kill $pid
  18335302+0 records in
  18335302+0 records out
  9387674624 bytes (9.4 GB) copied, 34.6279 seconds, 271 MB/s

With that basis, a little wrapper script could do what you want.