feat: add support for .NET SDK V4

[philasmar]

Issue #, if available:
DOTNET-7758

Description of changes:

• Updated .NET SDK project references to 4.0.0-preview.4
• Added .NET 8 target framework
• Enabled Trimming support
• Added SourceLink support
• Updated sample apps to new cs project styles

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[normj]

In the LogEventTransmissionSetup there needs to be a null check when checking the log group collection after calling DescribeLogGroupsAsync.

Also the the PutLogEventsRequest _request field in AWSLoggerCore is initialized the LogEvents collection is never initialized. I think you need to change the line

public PutLogEventsRequest _request = new PutLogEventsRequest();

to

public PutLogEventsRequest _request = new PutLogEventsRequest {LogEvents = new List<InputLogEvent>() };

Not related to your change but I don't know why the _request field is public. Can you try and make that private and see if there are any issues. My quick scan shows it only used in AWSLoggerCore.

[philasmar]

I addressed your comments.
As for the public field, it is defined inside the LogEventBatch class and then accessed from AWSLoggerCore. So it needs to be public.

[normj]

I wanted to build the packages locally to make sure they still looked right with all of the project file changes but I'm getting the following errors when I run dotnet msbuild build.proj

> dotnet msbuild .\build.proj
  build failed with 5 error(s) and 4 warning(s) (3.2s)
    C:\codebase\aws-logging-dotnet\test\AWS.Logger.SeriLog.Tests\AWS.Logger.SeriLog.Tests.csproj : error NU1903: Warning As Error: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-8g4q-xg66-9fp4 [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\test\AWS.Logger.AspNetCore.Tests\AWS.Logger.AspNetCore.Tests.csproj : error NU1903: Warning As Error: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-8g4q-xg66-9fp4 [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\test\AWS.Logger.AspNetCore.Tests\AWS.Logger.AspNetCore.Tests.csproj : error NU1903: Warning As Error: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-hh2w-p6rv-4g7w [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\test\AWS.Logger.SeriLog.Tests\AWS.Logger.SeriLog.Tests.csproj : error NU1903: Warning As Error: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-hh2w-p6rv-4g7w [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\samples\Serilog\SerilogTestCodeFromConfigRestrictedToMinimumLevel\SerilogTestCodeFromConfigRestrictedToMinimumLevel.csproj : warning NU1903: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-8g4q-xg66-9fp4 [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\samples\Serilog\SerilogTestCodeFromConfigRestrictedToMinimumLevel\SerilogTestCodeFromConfigRestrictedToMinimumLevel.csproj : warning NU1903: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-hh2w-p6rv-4g7w [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\samples\Serilog\SerilogTestCodeFromConfig\SerilogTestCodeFromConfig.csproj : warning NU1903: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-8g4q-xg66-9fp4 [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\samples\Serilog\SerilogTestCodeFromConfig\SerilogTestCodeFromConfig.csproj : warning NU1903: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-hh2w-p6rv-4g7w [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\build.proj(10,7): error MSB3073: The command "dotnet restore AWS.Logger.sln" exited with code 1.

[philasmar]

I wanted to build the packages locally to make sure they still looked right with all of the project file changes but I'm getting the following errors when I run dotnet msbuild build.proj

> dotnet msbuild .\build.proj
  build failed with 5 error(s) and 4 warning(s) (3.2s)
    C:\codebase\aws-logging-dotnet\test\AWS.Logger.SeriLog.Tests\AWS.Logger.SeriLog.Tests.csproj : error NU1903: Warning As Error: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-8g4q-xg66-9fp4 [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\test\AWS.Logger.AspNetCore.Tests\AWS.Logger.AspNetCore.Tests.csproj : error NU1903: Warning As Error: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-8g4q-xg66-9fp4 [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\test\AWS.Logger.AspNetCore.Tests\AWS.Logger.AspNetCore.Tests.csproj : error NU1903: Warning As Error: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-hh2w-p6rv-4g7w [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\test\AWS.Logger.SeriLog.Tests\AWS.Logger.SeriLog.Tests.csproj : error NU1903: Warning As Error: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-hh2w-p6rv-4g7w [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\samples\Serilog\SerilogTestCodeFromConfigRestrictedToMinimumLevel\SerilogTestCodeFromConfigRestrictedToMinimumLevel.csproj : warning NU1903: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-8g4q-xg66-9fp4 [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\samples\Serilog\SerilogTestCodeFromConfigRestrictedToMinimumLevel\SerilogTestCodeFromConfigRestrictedToMinimumLevel.csproj : warning NU1903: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-hh2w-p6rv-4g7w [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\samples\Serilog\SerilogTestCodeFromConfig\SerilogTestCodeFromConfig.csproj : warning NU1903: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-8g4q-xg66-9fp4 [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\samples\Serilog\SerilogTestCodeFromConfig\SerilogTestCodeFromConfig.csproj : warning NU1903: Package 'System.Text.Json' 8.0.0 has a known high severity vulnerability, https://github.com/advisories/GHSA-hh2w-p6rv-4g7w [C:\codebase\aws-logging-dotnet\AWS.Logger.sln]
    C:\codebase\aws-logging-dotnet\build.proj(10,7): error MSB3073: The command "dotnet restore AWS.Logger.sln" exited with code 1.

You are probably seeing those because you .NET9 installed. I didn't get those errors locally and in the build system with .NET8. I updated the problematic dependencies and tested them with .NET9.