build fixes

src/SharpCompress/Common/Rar/AsyncMarkingBinaryReader.cs

@@ -192,6 +192,7 @@ internal class AsyncMarkingBinaryReader : IDisposable
     }
 
     public virtual void Dispose() => _reader.Dispose();
+
 #if NET8_0_OR_GREATER
     public virtual ValueTask DisposeAsync() => _reader.DisposeAsync();
 #endif

src/SharpCompress/Compressors/LZMA/LzmaDecoder.Async.cs

@@ -9,8 +9,17 @@ using SharpCompress.Compressors.LZMA.RangeCoder;
 
 namespace SharpCompress.Compressors.LZMA;
 
-public partial class Decoder : ICoder, ISetDecoderProperties
+public partial class Decoder : IAsyncDisposable
 {
+    public async ValueTask DisposeAsync()
+    {
+        if (_outWindow is not null)
+        {
+            await _outWindow.DisposeAsync().ConfigureAwait(false);
+            _outWindow = null;
+        }
+    }
+
     partial class LenDecoder
     {
         public async ValueTask<uint> DecodeAsync(

src/SharpCompress/Compressors/LZMA/LzmaDecoder.cs

@@ -9,8 +9,14 @@ using SharpCompress.Compressors.LZMA.RangeCoder;
 
 namespace SharpCompress.Compressors.LZMA;
 
-public partial class Decoder : ICoder, ISetDecoderProperties // ,System.IO.Stream
+public partial class Decoder : ICoder, ISetDecoderProperties, IDisposable
 {
+    public void Dispose()
+    {
+        _outWindow?.Dispose();
+        _outWindow = null;
+    }
+
     private partial class LenDecoder
     {
         private BitDecoder _choice = new();

src/SharpCompress/Polyfills/StringExtensions.cs

@@ -1,4 +1,6 @@
-#if LEGACY_DOTNET
+using System;
+
+#if LEGACY_DOTNET
 
 namespace SharpCompress;
 
@@ -10,4 +12,9 @@ internal static class StringExtensions
     internal static bool Contains(this string text, char value) => text.IndexOf(value) > -1;
 }
 
+[AttributeUsage(
+    AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue
+)]
+public class NotNullAttribute : Attribute;
+
 #endif