The first example, reading lines in a file, is really slow. Depending on the input, it could be 4x-10x slower. In Go, the equivalent `ReadLine` is implemented on `bufio.Reader`. Thus the implementation can take advantage of the buffering.

In Zig, while this example does use a BufferedReader, the `streamUntilDelimiter` is implemented on the more generic `std.io.Reader` and thus cannot take full advantage of the buffering. It checks 1 byte at a time, and cannot leverage the SIMD-optimized `std.mem.indexOfScalar`.

Of course, you're free to create your own `readLines` that works against a BufferedReader. I do hope we'll see a whole version dedicated to review/polishing of the standard library. And maybe more work on composition, abstraction and interfaces.

The issue is described here: https://github.com/ziglang/zig/issues/17985