test "ArrayList outStream" {
    var a = std.ArrayList(u8).init(std.heap.page_allocator);
    _ = try a.append(1);
    _ = try a.append(2);
    var o = a.outStream();
    var f = o.writeInt(u8, 3, .Little);
    // var i = a.inStream();
    // inline for (std.meta.declarations(@TypeOf(o))) |decl| {
    //     std.debug.warn("decl {}\n", .{decl.name});
    // }

    for (a.toSliceConst()) |v, vi| {
        std.debug.warn("a[{}]={}\n", .{ vi, v });
    }
}