I had some old code that used buf.fill(null) for clearing up buffer contents. Looking at the docs I don't see it mentioned anywhere so I'm not sure if this is something I just came up or picked up from some sample code.

Anyway this used to work in v0.8 and v0.10 but doesn't work in v0.11. I bisected it to this change 4b40358 and because the commit message only mentions strings, I think the null behavior change may be unintentional.

So its something that is not documented/supported but has a potential to break old code.

Do you think this is worth to change the behavior to match old versions. Or should the function return an error for such input?

I could probably provide a PR.

/cc @trevnorris