An exercise in templating fast, resizable arrays for Cython that incur less Python overhead than the array module and expose a pure C representation which does not require any Python interaction.
The templated std::vector type in C++ is superior to these types in all ways but one, these
typed arrays support Python's buffer protocol.
This means that you can accumulate values in a nogil C context and then immediately pass
them along to NumPy without copying.