Tracking Issues:

• Add feature flag for Flexbox: Move flexbox code behind a default feature #298
• CSS Grid: Support CSS Grid #204
• Morphorm: Support Morphorm/Subform layout #308

This library will be dramatically more useful if it can be used to support multiple layout strategies. This is useful because:

• it centralizes community effort
• it enables fair benchmarks
• it lets users easily swap out approaches
• it creates the potential for blended layouts in the same app

Must have:

• each layout algorithm lives behind its own feature flag
• this crate provides a relatively unified interface to them
  • a trait seems like the natural fit here

Nice to have:

• low or zero abstraction overhead
• the ability to nest multiple distinct layout strategies, ala flutter
• competitive benchmarks between the different strategies
• rosetta-stone comparisons of practical examples, demonstrating how to create the same / comparable layouts in different paradigms
• users can create their own layout algorithms using our primitives in an interoperable way

Possible layout algorithms we may want to support:

• hstack / vstack
• Swift-UI style
• Flutter style
• CSS grid
• Morphorm
• Cassowary