upgrade fixes

src/ClamAV.Net/ClamAV.Net.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
 	<PropertyGroup>
-		<TargetFramework>netstandard2.1</TargetFramework>
+		<TargetFrameworks>netstandard2.1;netstandard2.0;</TargetFrameworks>
 		<GeneratePackageOnBuild>true</GeneratePackageOnBuild>
 		<Authors>petertsu@github</Authors>
 		<Product>ClamAV.Net</Product>
@@ -19,6 +19,7 @@
 		<Copyright>Copyright 2020 petertsu@github</Copyright>
 		<Summary>The ClamAV server .NETStandard client</Summary>
 		<ProjectGuid>4E284927-EFC1-443E-BC27-D598404ACE71</ProjectGuid>
+		<LangVersion>12.0</LangVersion>
 	</PropertyGroup>
 	<PropertyGroup>
 	  <DocumentationFile>ClamAV.Net.xml</DocumentationFile>

src/ClamAV.Net/Commands/InStreamCommand.cs

@@ -69,7 +69,11 @@ public ScanResult ProcessRawResponse(byte[] rawResponse)
                     new ClamAvException($"Invalid raw response '{actualResponse}'");
             }
 
+#if NETSTANDARD2_0
+            return new ScanResult(true, responseParts[responseParts.Length - 2]);
+#else
             return new ScanResult(true, responseParts[^2]);
+#endif
         }
     }
 }

src/ClamAV.Net/Socket/TcpSocketClient.cs

@@ -44,7 +44,7 @@ public async Task ConnectAsync(CancellationToken cancellationToken = default)
 
         private async Task<byte[]> ReadResponse(CancellationToken cancellationToken)
         {
-            await using MemoryStream memoryStream = new MemoryStream();
+            using MemoryStream memoryStream = new MemoryStream();
 
             do
             {

tests/ClamAV.Net.Tests/ClamAV.Net.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+	  <TargetFramework>netcoreapp8.0</TargetFramework>
 
     <IsPackable>false</IsPackable>
   </PropertyGroup>

tests/ClamAV.Net.Tests/Exceptions/ClamAvExceptionTests.cs

@@ -23,23 +23,5 @@ public void Ctor_Validation()
             clamAvException.Message.Should().Be(expectedMessage);
             clamAvException.InnerException.Should().NotBeNull();
         }
-
-        [Fact]
-        public void Serialization_Test()
-        {
-            const string expectedMessage = "Some error";
-            ClamAvException clamAvException = new ClamAvException(expectedMessage, new Exception("Error"));
-
-            BinaryFormatter binaryFormatter = new BinaryFormatter();
-
-            using MemoryStream memoryStream = new MemoryStream();
-            binaryFormatter.Serialize(memoryStream, clamAvException);
-            memoryStream.Seek(0, SeekOrigin.Begin);
-
-            ClamAvException actual = binaryFormatter.Deserialize(memoryStream) as ClamAvException;
-
-            actual.Should().NotBeNull();
-            actual.Should().BeEquivalentTo(clamAvException);
-        }
     }
 }