Use TryAdd()

Author: hishitetsu

src/Files.Shared/Extensions/LinqExtensions.cs

@@ -33,7 +33,7 @@ public static class LinqExtensions
 			if (!dictionary.ContainsKey(key))
 			{
 				if (defaultValue is TValue value)
-					dictionary.Add(key, value);
+					dictionary.TryAdd(key, value);
 
 				return defaultValue;
 			}
@@ -53,16 +53,8 @@ public static class LinqExtensions
 			{
 				var defaultValue = defaultValueFunc();
 				if (defaultValue is Task<TValue?> value)
-				{
-					if (dictionary is ConcurrentDictionary<TKey, Task<TValue?>> cDict)
-					{
-						cDict.TryAdd(key, value);
-					}
-					else
-					{
-						dictionary.Add(key, value);
-					}
-				}
+					dictionary.TryAdd(key, value);
+
 				return defaultValue;
 			}
 			return dictionary[key];