int32 FindIndex ( const void * Element, const [FScriptSetLayout](API\Runtime\Core\Containers\FScriptSetLayout) & Layout, [TFunctionRef](API\Runtime\Core\GenericPlatform\TFunctionRef)< uint32(const void *)> GetKeyHash, [TFunctionRef](API\Runtime\Core\GenericPlatform\TFunctionRef)< bool(const void *, const void *)> EqualityFn )