ResourceUsageStatistics

pub const ResourceUsageStatistics = struct {
    rusage: @TypeOf(rusage_init) = rusage_init,

    /// Returns the peak resident set size of the child process, in bytes,
    /// if available.
    pub inline fn getMaxRss(rus: ResourceUsageStatistics) ?usize {
        switch (native_os) {
            .dragonfly, .freebsd, .netbsd, .openbsd, .illumos, .linux, .serenity => {
                if (rus.rusage) |ru| {
                    return @as(usize, @intCast(ru.maxrss)) * 1024;
                } else {
                    return null;
                }
            },
            .windows => {
                if (rus.rusage) |ru| {
                    return ru.PeakWorkingSetSize;
                } else {
                    return null;
                }
            },
            .driverkit, .ios, .maccatalyst, .macos, .tvos, .visionos, .watchos => {
                if (rus.rusage) |ru| {
                    // Darwin oddly reports in bytes instead of kilobytes.
                    return @as(usize, @intCast(ru.maxrss));
                } else {
                    return null;
                }
            },
            else => return null,
        }
    }

    const rusage_init = switch (native_os) {
        .dragonfly,
        .freebsd,
        .netbsd,
        .openbsd,
        .illumos,
        .linux,
        .serenity,
        .driverkit,
        .ios,
        .maccatalyst,
        .macos,
        .tvos,
        .visionos,
        .watchos,
        => @as(?std.posix.rusage, null),
        .windows => @as(?std.os.windows.PROCESS.VM_COUNTERS, null),
        else => {},
    };
}