Working with preview features
It is a challenge for Microsoft to deliver some new features that have cross-cutting effects across many parts of .NET like the runtime, language compilers, and API libraries. It is the classic chicken and egg problem. What do you do first?
From a practical perspective, it means that although Microsoft might have completed the majority of the work needed for a feature, the whole thing might not be ready until very late in their now annual cycle of .NET releases, too late for proper testing in "the wild."
So, from .NET 6 onward, Microsoft will include preview features in general availability (GA) releases. Developers can opt into these preview features and provide Microsoft with feedback. In a later GA release, they can be enabled for everyone.
Good Practice: Preview features are not supported in production code. Preview features are likely to have breaking changes before the final release. Enable preview features at your own...