v2.0.2

Fixes:

• Fixed Promise.AwaitWithProgress not working in IL2CPP.
• Fixed a rare race condition where a canceled promise could cause an invalid cast exception.

Optimizations:

• Fixed boxing nullable value-types.
• Reduced size of cancelable promises.
• Subscribing to progress now runs in O(1) time and consumes O(1) memory, down from O(n) for both.

Misc:

• Increased precision of progress, from 1/(2^13) to 1/(2^16).