Remove GetOrAdd extension method

Assets/Reflex/Caching/TypeConstructionInfoCache.cs

@@ -13,7 +13,13 @@ internal static class TypeConstructionInfoCache
 
         internal static TypeConstructionInfo Get(Type type)
         {
-            return _dictionary.GetOrAdd(type, Generate);
+            if (!_dictionary.TryGetValue(type, out var info))
+            {
+                info = Generate(type);
+                _dictionary.Add(type, info);
+            }
+
+            return info;
         }
 
         private static TypeConstructionInfo Generate(Type type)

Assets/Reflex/Core/ContainerBuilder.cs

@@ -35,7 +35,12 @@ public Container Build()
 
                 foreach (var contract in binding.Contracts)
                 {
-                    var resolvers = resolversByContract.GetOrAdd(contract, _ => new List<IResolver>());
+                    if (!resolversByContract.TryGetValue(contract, out var resolvers))
+                    {
+                        resolvers = new List<IResolver>();
+                        resolversByContract.Add(contract, resolvers);
+                    }
+
                     resolvers.Add(binding.Resolver);
                 }
             }