message: add a hash function to use with smart_refctd_ptr
diff: @@ -212,6 +212,14 @@ namespace core
  using pointee = I_REFERENCE_COUNTED;
  using value_type = I_REFERENCE_COUNTED*;
  + struct hash
  + {
  + inline size_t operator() (const core::smart_refctd_ptr<I_REFERENCE_COUNTED>& ptr) const
  + {
  + return std::hash<void*>{}(ptr.get());
  + }
  + };
  +
  constexpr smart_refctd_ptr() noexcept : ptr(nullptr) {}
  constexpr smart_refctd_ptr(std::nullptr_t) noexcept : ptr(nullptr) {}
  template<class U>
  