Files
SwiftLint/Source/SwiftLintFramework
JP Simard 3a32d6b479 Speed up reading cached results by about 200%
also slightly speed up writing to the cache.

For example, on the Lyft codebase with 1,500 Swift files:

```bash
$ time swiftlint lint --quiet
swiftlint --quiet  3.53s user 0.27s system 388% cpu 0.979 total
$ rm -rf ~/Library/Caches/SwiftLint && time swiftlint lint --quiet
swiftlint --quiet  35.20s user 1.22s system 371% cpu 9.806 total
$ time swiftlint lint --quiet
swiftlint lint --quiet  0.90s user 0.13s system 218% cpu 0.472 total
$ rm -rf ~/Library/Caches/SwiftLint && time swiftlint lint --quiet
swiftlint lint --quiet  31.78s user 1.18s system 360% cpu 9.146 total
```
2017-10-19 23:17:01 -07:00
..
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