Delay file removal to fix vim backupcopy issue

[es128]

I wasn't able to reproduce the issue actually using vim, but I was able to do so using the mv file.js file.js.swp && sleep .1 && mv file.js.swp file.js emulation method. This patch does appear to cause the desired behavior of handling the event as a change instead of an unlink with no subsequent add.

Aside from a very slight delay in unlink events, I am not sure whether this will lead to unwanted side-effects. It would be great if people could try it out with various use-cases to see how it goes - particularly those who can consistently make it happen with vim.

[paulmillr]

need someone with vim to test this out because it can bring unwanted bugs

[andrewrk]

this code looks suspicious. what exactly are you trying to do?

[es128]

Haha, suspicious? It's pretty straightforward, albeit a bit hacky. Take a look at #35 if you haven't already to understand the problem this is trying to solve. In that thread, I mentioned an idea a while ago about a possible solution. I tried it out today and it seemed to work, hence the PR.

That said, it isn't something I am affected by personally, and I couldn't even recreate the reported issue using vim. But this keeps coming up with brunch users, so that was my motivation to attempt a fix.

I agree with @paulmillr that we need some users who were affected by and able to recreate the vim issue to try this out and provide feedback before this is considered for merging.