Add generic EnumCache

Author: notfood

Source/Common/ByteReader.cs

@@ -140,7 +140,7 @@ public virtual ulong[] ReadPrefixedULongs()
 
         public virtual T ReadEnum<T>() where T : Enum
         {
-            var values = EnumCache.GetValues(typeof(T));
+            var values = EnumCache<T>.Values;
             ushort enumIndex = values.Length switch
             {
                 <= byte.MaxValue => ReadByte(),

Source/Common/ByteWriter.cs

@@ -5,6 +5,7 @@
 using System.Runtime.CompilerServices;
 using System.Text;
 using Multiplayer.Common.Util;
+using Verse;
 
 namespace Multiplayer.Common
 {
@@ -86,7 +87,7 @@ public virtual ByteWriter WriteString(string? s)
 
         public virtual void WriteEnum<T>(T value) where T : Enum
         {
-            var values = EnumCache.GetValues(value.GetType());
+            var values = typeof(T) == typeof(Enum) ? EnumCache.Values(value.GetType()) : EnumCache<T>.Values;
             var index = Array.IndexOf(values, value);
             switch (values.Length)
             {

Source/Common/Util/EnumCache.cs

@@ -1,11 +1,17 @@
 using System;
 using System.Collections.Concurrent;
+using System.Linq;
 
 namespace Multiplayer.Common.Util;
 
+internal static class EnumCache<T> where T: Enum
+{
+    public static readonly T[] Values = Enum.GetValues(typeof(T)).Cast<T>().ToArray();
+}
+
 internal static class EnumCache
 {
     private static readonly ConcurrentDictionary<Type, Array> Cache = new();
 
-    public static Array GetValues(Type enumType) => Cache.GetOrAdd(enumType, Enum.GetValues);
-}
+    public static Array Values(Type enumType) => Cache.GetOrAdd(enumType, Enum.GetValues);
+}