## Proposed Changes
Speed up epoch processing by around 10% by inlining methods from the `safe_arith` crate.
The Rust standard library uses `#[inline]` for the `checked_` functions that we're wrapping, so it makes sense for us to inline them too.
## Additional Info
I conducted a brief statistical test on the block at slot [3858336](https://beaconcha.in/block/3858336) applied to the state at slot 3858335, which requires an epoch transition. The command used for testing was:
```
lcli transition-blocks --testnet-dir ./common/eth2_network_config/built_in_network_configs/mainnet --no-signature-verification state.ssz block.ssz output.ssz
```
The testing found that inlining reduced the epoch transition time from 398ms to 359ms, a reduction of 9.77%, which was found to be statistically significant with a two-tailed t-test (p < 0.01). Data and intermediate calculations can be found here: https://docs.google.com/spreadsheets/d/1tlf3eFjz3dcXeb9XVOn21953uYpc9RdQapPtcHGH1PY
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