alias
   Mocks::Registry::Key
  
  Overview
Entry keys consist of two elements - the type ID and it's location in memory. For value-types, its byte-representation is stored in a pool and that location is used.
WARNING  The Class#crystal_type_id method, which is undocumented, is used to retrieve the first part of the key.
NOTE  Ideally, the type would be used as the first element of the tuple.
Object.class cannot be used due to https://github.com/crystal-lang/crystal/issues/9667
Alias Definition
{Int32, UInt64}