diff --git a/src/ZeroLog.Impl.Base/LogManager.cs b/src/ZeroLog.Impl.Base/LogManager.cs
index 4f8aa28..3977922 100644
--- a/src/ZeroLog.Impl.Base/LogManager.cs
+++ b/src/ZeroLog.Impl.Base/LogManager.cs
@@ -20,6 +20,9 @@ public sealed partial class LogManager
     /// </remarks>
     /// <typeparam name="T">The type.</typeparam>
     public static Log GetLogger<T>()
+#if NET9_0_OR_GREATER
+        where T : allows ref struct
+#endif
         => GetLogger(typeof(T));
 
     /// <summary>
diff --git a/src/ZeroLog.Impl.Full/BufferSegmentProvider.cs b/src/ZeroLog.Impl.Full/BufferSegmentProvider.cs
index cb4b000..ffb19dc 100644
--- a/src/ZeroLog.Impl.Full/BufferSegmentProvider.cs
+++ b/src/ZeroLog.Impl.Full/BufferSegmentProvider.cs
@@ -4,7 +4,11 @@ namespace ZeroLog;
 
 internal unsafe class BufferSegmentProvider
 {
-    private readonly object _lock = new();
+#if NET9_0_OR_GREATER
+    private static readonly System.Threading.Lock _lock = new();
+#else
+    private static readonly object _lock = new();
+#endif
 
     private readonly int _segmentCount;
     private readonly int _segmentSize;
diff --git a/src/ZeroLog.Impl.Full/Runner.cs b/src/ZeroLog.Impl.Full/Runner.cs
index 42d1473..754ae96 100644
--- a/src/ZeroLog.Impl.Full/Runner.cs
+++ b/src/ZeroLog.Impl.Full/Runner.cs
@@ -310,7 +310,11 @@ public override void Flush()
 
 internal sealed class SyncRunner(ZeroLogConfiguration config) : Runner(config)
 {
-    private readonly object _lock = new();
+#if NET9_0_OR_GREATER
+    private static readonly Lock _lock = new();
+#else
+    private static readonly object _lock = new();
+#endif
 
     public override void Submit(LogMessage message)
     {
diff --git a/src/ZeroLog.Impl.Full/UnmanagedCache.cs b/src/ZeroLog.Impl.Full/UnmanagedCache.cs
index a1bfab3..9a73f40 100644
--- a/src/ZeroLog.Impl.Full/UnmanagedCache.cs
+++ b/src/ZeroLog.Impl.Full/UnmanagedCache.cs
@@ -31,6 +31,12 @@ internal delegate bool FormatterDelegate(
         ZeroLogConfiguration config
     );
 
+#if NET9_0_OR_GREATER
+    private static readonly System.Threading.Lock _lock = new();
+#else
+    private static readonly object _lock = new();
+#endif
+
     private static readonly Dictionary<IntPtr, FormatterDelegate> _unmanagedStructs = new();
     private static readonly MethodInfo _registerMethod = typeof(UnmanagedCache).GetMethod(nameof(Register), Type.EmptyTypes)!;
 
@@ -52,7 +58,7 @@ public static void Register<T>(UnmanagedFormatterDelegate<T> formatter)
     {
         ArgumentNullException.ThrowIfNull(formatter);
 
-        lock (_unmanagedStructs)
+        lock (_lock)
         {
             _unmanagedStructs[typeof(T).TypeHandle.Value] = (byte* valuePtr, Span<char> destination, out int charsWritten, ReadOnlySpan<char> format, ZeroLogConfiguration _)
                 => FormatterGeneric(valuePtr, destination, out charsWritten, format, formatter);
@@ -109,7 +115,7 @@ private static bool FormatterGenericNullable<T>(byte* valuePtr,
     public static bool TryGetFormatter(IntPtr typeHandle, out FormatterDelegate formatter)
     {
         // This is accessed from a single thread, there should be no contention
-        lock (_unmanagedStructs)
+        lock (_lock)
         {
             return _unmanagedStructs.TryGetValue(typeHandle, out formatter!);
         }
diff --git a/src/ZeroLog.Tests/PerformanceTests.cs b/src/ZeroLog.Tests/PerformanceTests.cs
index 59ecf01..9c60de9 100644
--- a/src/ZeroLog.Tests/PerformanceTests.cs
+++ b/src/ZeroLog.Tests/PerformanceTests.cs
@@ -55,7 +55,7 @@ public void should_run_test()
         var signal = _testAppender.SetMessageCountTarget(totalMessageCount);
         var utcNow = DateTime.UtcNow;
 
-        Parallel.For(0, threadCount, i =>
+        Parallel.For(0, threadCount, _ =>
         {
             for (var k = 0; k < threadMessageCount; k++)
             {
diff --git a/src/ZeroLog.Tests/Support/AssertExtensions.cs b/src/ZeroLog.Tests/Support/AssertExtensions.cs
index 5bffecb..3e8cee4 100644
--- a/src/ZeroLog.Tests/Support/AssertExtensions.cs
+++ b/src/ZeroLog.Tests/Support/AssertExtensions.cs
@@ -7,6 +7,9 @@ namespace ZeroLog.Tests.Support;
 
 #nullable enable
 
+#if NET6_0_OR_GREATER
+[System.Diagnostics.StackTraceHidden]
+#endif
 internal static class AssertExtensions
 {
     public static void ShouldEqual<T>(this T? actual, T? expected)