Merge pull request #168 from AArnott/fix167

Fix Sequence<T> to work for managed types T

Author: AArnott

src/Nerdbank.Streams.Tests/SequenceTests.cs

@@ -486,6 +486,16 @@ public void Dispose_ClearsAndAllowsReuse()
         Assert.Equal(3, seq.AsReadOnlySequence.Length);
     }
 
+    [Fact]
+    public void SequenceOfManagedType()
+    {
+        var seq = new Sequence<object>();
+        seq.Write(new object[] { new object(), new object() });
+        Assert.Equal(2, seq.Length);
+        Assert.IsType<object>(seq.AsReadOnlySequence.First.Span[0]);
+        Assert.IsType<object>(seq.AsReadOnlySequence.First.Span[1]);
+    }
+
     /// <summary>
     /// Adds a reference to an object in the sequence and returns a weak reference to it.
     /// </summary>

src/Nerdbank.Streams/Nerdbank.Streams.csproj

@@ -23,6 +23,7 @@
     <PackageReference Include="System.Buffers" Version="4.5.0" />
     <PackageReference Include="System.IO.Pipelines" Version="4.5.3" />
     <PackageReference Include="System.Net.WebSockets" Version="4.3.0" />
+    <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="4.6.0" />
     <PackageReference Include="System.ValueTuple" Version="4.5.0" />
   </ItemGroup>
   <ItemGroup>

src/Nerdbank.Streams/Sequence`1.cs

@@ -23,7 +23,7 @@ namespace Nerdbank.Streams
     [DebuggerDisplay("{" + nameof(DebuggerDisplay) + ",nq}")]
     public class Sequence<T> : IBufferWriter<T>, IDisposable
     {
-        private static readonly int DefaultLengthFromArrayPool = 1 + (4095 / Marshal.SizeOf<T>());
+        private static readonly int DefaultLengthFromArrayPool = 1 + (4095 / Unsafe.SizeOf<T>());
 
         private static readonly ReadOnlySequence<T> Empty = new ReadOnlySequence<T>(SequenceSegment.Empty, 0, SequenceSegment.Empty, 0);