packages/ parallel race condition

[haf-lynx]

If MsBuild is used to build the solution with paket in parallel, then the lock implementation in Paket is broken; see 66ca1d5#commitcomment-19267997 for details and suggested solution.

This issue is identical to the closed issue #858

I may not have identified our interleaving, but the end result is a never-finishing build because some lock never is released, so progress cannot be made.

[forki]

Are you up to send a PR? Or do you know someone who might be interested in fixing it?

[mattrrichard]

What about only running paket once per solution instead of once per project? I know there's no "before solution" event, but can we come up with a way to make it work?