fn fileSeekTo(userdata: ?*anyopaque, file: File, offset: u64) File.SeekError!void
fn fileSeekTo(userdata: ?*anyopaque, file: File, offset: u64) File.SeekError!void { const ev: *Evented = @ptrCast(@alignCast(userdata)); return ev.lseek(file.handle, offset, c.SEEK.SET); }