Possible bugfix for CollisionBag and Suggestions

[flitzi]

• there was some threadlocking missing in CollisionBag
• a bit cleaner IsActive
• use ThreadPool.QueueUserWorkItem() instead of new Thread().Start() for short operations

[flitzi]

To be honest I think it's very unlikely that this really was the problem with the Collisions, but these changes shouldn't hurt either.

The problem with the threadlocking was mainly that reading and writing DateTime struct is not atomic so you might read corrupt values.

[flitzi]

the locking with bag.lockObject is done to make sure that TryAdd and the check in the Loop in StartNew is not done in parallel which might cause Problems.

Yes, the ThreadPool has less overhead and in our cases here there should there shouldn't be any delay.

[minolin]

Thank you then!