Convert pointers to span in System.Net.Primitives

[EgorBo]

IPAddress and Uri parsing are heavily relying on raw pointers making code extremely difficult to validate we never go out of bounds. I wonder what is the performance impact if we convert them all to Span.. Obviously, in most cases it will lead to redundant bounds checks that JIT is unlikely to remove due to complex loop shapes, implicit/IPA assumptions, etc..

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[stephentoub]

(When I previously experimented with this it was quite measurable, but maybe things have improved since then.)

[EgorBo]

@EgorBot -intel -arm

using BenchmarkDotNet.Attributes;

public class UriParsingBenchmarks
{
    public static IEnumerable<string> GetTestData() => new[]
    {
        "https://alice:pa%24%24@例子.com/テスト",
        "https://bob%40dev:%F0%9F%92%[email protected]/💾/ファイル",
        "https://user:pwd%40key@пример.тест/данные/測試?mode=%E6%A4%9C%E8%A8%BC",
        "https://user:pa%24%[email protected]/路径/данные/資料",
        "https://data:tok3n@服务.cn/文件/📊/統計?state=%7B%22ok%22%3Atrue%2C%22v%22%3A%22%25done%25%22%7D",
        "https://token%3Auser:secr%25et@ドメイン.example/分析/データ/данные",
        "https://üser:päss@пример.com/страница/テスト?lang=日本語",
        "https://john:doe%21pass@δοκιμή.gr/δοκιμή/資料?ref=abc%25xyz",
        "https://账号:密码@例え.テスト/画像/файлы?タグ=猫%20写真",
        "https://x:y%25z@データ.jp/経路/данные/🧠/研究?city=Z%C3%BCrich&lang=%E6%97%A5%E6%9C%AC%E8%AA%9E"
    };

    // Baseline: construct a Uri
    [Benchmark(Baseline = true)]
    [ArgumentsSource(nameof(GetTestData))]
    public Uri NewUri(string uri) => new (uri);
}