com.unity.collections 2.6.0-pre.3 Package Notes

`threadIndexOverride` method overloads for `ParallelWriter.Add/TryAdd` operations for `NativeParallelHashMap`, `UnsafeParallelHashMap`, `NativeParallelHashSet`, `UnsafeParallelHashSet`, `NativeQueue`, `UnsafeQueue`, `NativeParallelMultiHashMap`, and `UnsafeParallelMultiHashMap`. These overloads allow some performance critical use-cases to sub-divide work that would previously be forced against a single collection, by enabling the (unsafe) injection of many instances of these collections (via their respective `ParallelWriter`s) into the same job. For example, this would allow you to convert a `NativeParallelMultiHashMap,TValue>.ParallelWriter` pattern into an (unsafe) `NativeList.ParallelWriter>[TIndex]` pattern, which can; reduce individual collection capacities, reduce insertion/removal/clear call overheads, reduce the need to manually sort (or otherwise post-process) collection results, and allow better segmentation of work (i.e. higher granularity).

UnsafeQueue memory leak due to OnDomainUnload callback being discarded by Burst.
Fixed incorrect error message when a NativeStream foreach index is out-of-range.