Non-BoxingEnumDictExample.cs

private Dictionary<ComponentTypesEnum, List<ComponentEcs>> _componentPools =
			new Dictionary<ComponentTypes, List<ComponentEcs>>(new FastEnumIntEqualityComparer<ComponentTypes>()); // This is the custom comparator passed into the dict constructor
      
struct FastEnumIntEqualityComparer<TEnum> : IEqualityComparer<TEnum>
		where TEnum : struct
	{
		static class BoxAvoidance
		{
			static readonly Func<TEnum, int> _wrapper;

			public static int ToInt(TEnum enu)
			{
				return _wrapper(enu);
			}

			static BoxAvoidance()
			{
				var p = Expression.Parameter(typeof(TEnum), null);
				var c = Expression.ConvertChecked(p, typeof(int));

				_wrapper = Expression.Lambda<Func<TEnum, int>>(c, p).Compile();
			}
		}

		public bool Equals(TEnum firstEnum, TEnum secondEnum)
		{
			return BoxAvoidance.ToInt(firstEnum) ==
				BoxAvoidance.ToInt(secondEnum);
		}

		public int GetHashCode(TEnum firstEnum)
		{
			return BoxAvoidance.ToInt(firstEnum);
		}
	}