On my extremely old desktop PC (Phenom II 550) running an out-of-date OS (Slackware 14.2):

Bash:

    while :; do printf "1"; done  | ./pv > /dev/null
    [ 156KiB/s]

Python3 3.7.2:

    python3 -c 'while (1): print (1, end="")' | ./pv > /dev/null
    [1,02MiB/s]

Perl 5.22.2:

    perl -e 'while (true) {print 1}'  | ./pv > /dev/null
    [3,03MiB/s]

Node.js v12.22.1:

    node -e 'while (1) process.stdout.write("1");' | ./pv > /dev/null
    [ 482KiB/s]