pub fn failingDirOpenFile(userdata: ?*anyopaque, dir: Dir, sub_path: []const u8, flags: Dir.OpenFileOptions) File.OpenError!File
pub fn failingDirOpenFile(userdata: ?*anyopaque, dir: Dir, sub_path: []const u8, flags: Dir.OpenFileOptions) File.OpenError!File { _ = userdata; _ = dir; _ = sub_path; _ = flags; return error.FileNotFound; }