fs.write(v) is not guaranteed to write everything in a single
call. Make sure we don't assume so.
PR-URL: https://github.com/nodejs/node/pull/49211
Co-authored-by: Chemi Atlow <chemi@atlow.co.il>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Robert Nagy <ronagy@icloud.com>
