internally, I believe this is implemented as a while(COND) { ... } continue { ... }

Yes, it is:

lorenzo@alice:~$ perl -MO=Deparse,-x3 -e 'for( my $i = 0; $i < 10; $i+
++ ) {}'
while ($i < 10) {
    ;
}
continue {
    ++$i
}
-e syntax OK
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