Backport data corruption bugfix (#75, #76) to CJS

[haggholm]

Nearly 80% of active users of this library use the CJS version, presumably because many people are stuck on projects that cannot easily be migrated to ESM—or are consuming fs-capacitor via libraries that are still published using CJS.

This means that the large majority of users are potentially exposed to #75, which is pretty severe: a silent data corruption bug.

While I do not expect that you want to go back to CJS, and I understand that future feature development will likely be ESM only, it would seem reasonable to me to backport a fix for a bug that critical to the 6.x branch, which is by far the most widely used.

[airhorns]

In the same boat -- really sucks to have to upgrade an entire (potentially very big) app to ESM everywhere in order to get this one critical bug fix out. For my team, we're blocked by a critical Jest bug where it segfaults when requiring ESM code sometimes, so we can't even move to ESM without also changing test runners. Any chance for a backported fix?