@nogc @system nothrow unittest{    import std.experimental.allocator.mallocator;     auto buffer = Mallocator.instance.allocate(1024 * 1024 * 4);    scope(exit) Mallocator.instance.deallocate(buffer);    //...} pure @nogc @system nothrow unittest{    import std.experimental.allocator.mallocator;     auto buffer = AlignedMallocator.instance.alignedAllocate(1024 * 1024 * 4,        128);    scope(exit) AlignedMallocator.instance.deallocate(buffer);    //...}