Here's what the OP of the PostgresNIO issue has mentioned about what performance impact usage of `file_copy` has in his setup (https://github.com/SwiftPackageIndex/SwiftPackageIndex-Server/pull/3812):
`Series: Default Strategy Suite AllTests passed after 5.081 seconds Suite AllTests passed after 5.274 seconds Suite AllTests passed after 5.306 seconds Suite AllTests passed after 5.224 seconds Suite AllTests passed after 6.343 seconds Suite AllTests passed after 5.450 seconds Series: file_copy Strategy Suite AllTests passed after 4.729 seconds Suite AllTests passed after 4.755 seconds Suite AllTests passed after 4.739 seconds Suite AllTests passed after 4.772 seconds Suite AllTests passed after 4.866 seconds Suite AllTests passed after 4.855 seconds` This is them running the tests in parallel multiple times with and without file_copy, just to benchmark. Overall ~0.5-6s / ~10% speedup, which isn't too significant at this level, but is still a noticeable relative improvement.
