.NET 11 Preview 2: Performance Boosts & Key Dev Enhancements

Unpacking .NET 11 Preview 2's Developer Impact

The release of .NET 11 Preview 2 signals a maturing and performance-focused development cycle for Microsoft's flagship platform. The integration of native OpenTelemetry tracing in ASP.NET Core is a particularly noteworthy advancement. By automatically populating semantic attributes for HTTP server activity, developers are relieved of the burden of manual instrumentation for common tracing scenarios. This not only streamlines observability but also ensures a more consistent and accurate data collection pipeline. The performance gains in Kestrel's HTTP/1.1 parser, especially in high-invalid-traffic situations, are also crucial for building resilient and efficient web applications. Furthermore, the introduction of the dotnet new webworker template for Blazor WebAssembly directly addresses a critical need for offloading heavy computations without compromising UI responsiveness, a common challenge in modern web development.

The enhancements to .NET MAUI, including simplified XAML map definitions, visibility toggling for map elements, and improved click event handling, signify a commitment to making cross-platform UI development more intuitive and powerful. The substantial binding performance improvements and the resolution of the empty-string binding bug further contribute to a more robust and developer-friendly mobile and desktop development experience. For the F# community, the addition of #elif for conditional compilation and the partitionWith function offer practical improvements for code organization and data manipulation. The focus on reducing type-checking time and providing Big-O complexity notes directly in IDE tooltips demonstrates a keen awareness of developer productivity and the importance of performance at the language level. This preview release showcases a well-rounded approach to enhancing the .NET ecosystem across its various components, from web services to cross-platform applications and functional programming paradigms.

Key Points

• ASP.NET Core now offers native OpenTelemetry tracing support, automatically adding semantic attributes to HTTP server activity.
• Blazor Server-Side Rendering gains TempData support for persisting data across requests.
• A new dotnet new webworker template allows Blazor WebAssembly to offload heavy computations to a Web Worker.
• Kestrel's HTTP/1.1 request parser is reworked, improving throughput by 20-40% in high invalid-traffic scenarios.
• .NET MAUI's Map control features simplified XAML coordinate definition, bindable Map.Region, visibility toggling and ZIndex for map elements, and click event support.
• .NET MAUI binding performance sees significant improvements (approx. 29% faster, 50% less memory allocation) with TypedBinding and SourceGeneratedBinding.
• A long-standing bug with empty-string binding to nullable value types in .NET MAUI is resolved.
• F# gains #elif preprocessor directive support and a new partitionWith function.
• F# type-checking performance is improved with a new overload resolution caching mechanism.
• Core F# collection modules now include Big-O complexity notes in IDE tooltips.
• Other improvements include generic GetTypeInfo for System.Text.Json and a 15% performance boost to Matrix4x4.GetDeterminant.

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📖 Source: .NET 11 Preview 2 Brings Performance Gains, Improved Mapping, and Native OpenTelemetry Support