Unlike most of the other backports, this code couldn't be directly
translated so it had to be re-implemented. Luckily, it is very simple.
This implementation is a bit messy and heavy handed with potential
panics, but I think it's probably fine since file names that aren't
UTF-8 aren't really supported anyway. The original implementation is a
lot cleaner though.
The test snapshots are (almost) all identical between the 7.5
implementation and this one. The sole exception is with the path in the
`snapshot_middleware::project` test, since I didn't feel like adding a
`name` parameter to `snapshot_project` in this implementation.
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