Create and use FormattingStreamWriter

Prevents bugs causes by system cultures with different formatting

tests/Jellyfin.Extensions.Tests/FormattingStreamWriterTests.cs

@@ -0,0 +1,23 @@
+using System.Globalization;
+using System.IO;
+using System.Text;
+using System.Threading;
+using Xunit;
+
+namespace Jellyfin.Extensions.Tests;
+
+public static class FormattingStreamWriterTests
+{
+    [Fact]
+    public static void Shuffle_Valid_Correct()
+    {
+        Thread.CurrentThread.CurrentCulture = new CultureInfo("de-DE", false);
+        using (var ms = new MemoryStream())
+        using (var txt = new FormattingStreamWriter(ms, CultureInfo.InvariantCulture))
+        {
+            txt.Write("{0}", 3.14159);
+            txt.Close();
+            Assert.Equal("3.14159", Encoding.UTF8.GetString(ms.ToArray()));
+        }
+    }
+}