Variant

This is an attempt to implement an interface similar to std::variant. https://en.cppreference.com/w/cpp/utility/variant

Some differences are:

• Only single instance of a type T is allowed.
• No std::monostate default construction support

Doing the above will result in UB.

How it works

Every instance of a variant construct a buffer on the heap which is the size of the largest element in the parameter pack. Upon modification, the same buffer is used to placement new and delete in order to destruct the old element and construct the new one.

To Do:

Next step is to add a std::visit implementation as well.