fix: make sure manifest writes don't overlap

[mastilver]

closes #21

[codecov-io]

Codecov Report

Merging #56 into master will decrease coverage by 0.93%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #56      +/-   ##
==========================================
- Coverage     100%   99.06%   -0.94%     
==========================================
  Files           2        2              
  Lines          56      107      +51     
==========================================
+ Hits           56      106      +50     
- Misses          0        1       +1

Impacted Files	Coverage Δ
lib/plugin.js	99.05% <100%> (-0.95%)	:arrow_down:

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[zuzusik]

The main question here - does it really fix #21? I don't see an appropriate test case added here. If it is hard to reproduce maybe we should ask reporters of #21 to test this fix with their local setup?

If it doesn't fix #21 then I don't see why it should be merged. As a step for #33 as supposed here https://github.com/danethurber/webpack-manifest-plugin/issues/33#issuecomment-314063783 ? Don't think we need this step - we better fix #33 with one monolithic PR

[mastilver]

@zuzusik Thank you for reviewing this PR :)

Did you see #49, I think you could be a good help for me

I think I know what's causing the issue, I will try to write a test that reproduce it

[zuzusik]

Also added few style related comments here

[zuzusik]

One serious concern here: https://github.com/danethurber/webpack-manifest-plugin/pull/56/files#r126405642

[mastilver]

@zuzusik PR updated, do you mind having another look

[mastilver]

@zuzusik I'm not relying anymore or memory-fslogic

Let me know what you think!