812c21e2e4 refactor: Replace fold with try_fold (yancy)
Pull request description:
The and_then combinator performs a kind of bitwise and operation on two Option types here. This is useful since the `checked` arithmetic returns an option thereby accumulating Option types. Therefore, either the checked arithmetic operation performs the addition of the unwrapped accumulator, or it returns None.
Instead of using `and_then` use the provided `try_fold` method which will short circuit on `None` when the checked arithmetic is used. Also, simplify the staring condition using `Amount:ZERO` since this is logically equivalent to using the first value if one exists.
Lastly, by using the built in `try_fold`, it's possible the performance will be improved by making use of the short circuit ability instead of evaluating each item even when the accumulator holds a None type.
ACKs for top commit:
apoelstra:
ACK 812c21e2e4a868046b44728c1a6209a866452820; successfully ran local tests
tcharding:
ACK 812c21e2e4
Tree-SHA512: 1cfcd4fa28e2b59daf3744bb5f654f65eb9853c5a36f747cb0859783e7e46c1d02ccb296612b75f7cca10782979ce052cd670c0f23c1030e0a347000d1f6df83
551b52c7d1