revert lock

Author: mythz

src/ServiceStack.Text/Common/WriteDictionary.cs

@@ -72,9 +72,8 @@ public override int GetHashCode()
         public static Action<TextWriter, object, WriteObjectDelegate, WriteObjectDelegate>
             GetWriteGenericDictionary(Type keyType, Type valueType)
         {
-            WriteMapDelegate writeFn;
             var mapKey = new MapKey(keyType, valueType);
-            if (CacheFns.TryGetValue(mapKey, out writeFn)) return writeFn.Invoke;
+            if (CacheFns.TryGetValue(mapKey, out var writeFn)) return writeFn.Invoke;
 
             var genericType = typeof(ToStringDictionaryMethods<,,>).MakeGenericType(keyType, valueType, typeof(TSerializer));
             var mi = genericType.GetStaticMethod("WriteIDictionary");
@@ -239,7 +238,6 @@ public static void WriteGenericIDictionary(
                     {
                         writeKeyFn(writer, kvp.Key);
                     }
-
                 }
                 finally
                 {

src/ServiceStack.Text/StringExtensions.cs

@@ -534,16 +534,11 @@ public static T FromJsvSpan<T>(this ReadOnlySpan<char> jsv)
             return TypeSerializer.DeserializeFromSpan<T>(jsv);
         }
 
-        static readonly object semaphore = new object(); //tmp workaround async multi-threading 
-
         public static string ToJson<T>(this T obj)
         {
-            lock (semaphore)
-            {
-                return JsConfig.PreferInterfaces
-                    ? JsonSerializer.SerializeToString(obj, AssemblyUtils.MainInterface<T>())
-                    : JsonSerializer.SerializeToString(obj);
-            }
+            return JsConfig.PreferInterfaces
+                ? JsonSerializer.SerializeToString(obj, AssemblyUtils.MainInterface<T>())
+                : JsonSerializer.SerializeToString(obj);
         }
 
         public static string ToSafeJson<T>(this T obj)