--limit-rate=amount
       Limit the download speed to amount bytes per second.  Amount may be
       expressed in bytes, kilobytes with the k suffix, or megabytes  with
       the  m  suffix.   For  example,  --limit-rate=20k  will  limit  the
       retrieval rate to  20KB/s.   This  is  useful  when,  for  whatever
       reason,  you  don't  want  Wget  to  consume  the  entire available
       bandwidth.

       This  option  allows  the  use  of  decimal  numbers,  usually   in
       conjunction  with power suffixes; for example, --limit-rate=2.5k is
       a legal value.

       Note that Wget implements the limiting by sleeping the  appropriate
       amount  of  time  after  a  network  read  that took less time than
       specified by the rate.  Eventually this  strategy  causes  the  TCP
       transfer   to  slow  down  to  approximately  the  specified  rate.
       However, it may take some time for this balance to be achieved,  so
       don't be surprised if limiting the rate doesn't work well with very
       small files.

wget -c --limit-rate=500K https://iiiypuk.me/Koe_no_Katachi.mkv