This commit adds subtree memoization to Dioxus.
Subtree memoization is basically a compile-time step that drastically
reduces the amount of work the diffing engine needs to do at runtime by
extracting non-changing nodes out into a static "template." Templates
are then understood by the various renderers in the ecosystem as a
faster way of rendering the same items.
For example, in the web, templates are simply a set of DOM Nodes created
once and then cloned later. This is the same pattern frameworks like Lithtml
and SolidJS use to achieve near-perfect performance.
Subtree memoization adds an additional level of complexity to Dioxus. The RSX
macro needs to be much smarter to identify changing/nonchanging nodes and
generate a mapping between the Template and its runtime counterparts.
This commit represents a working starter point for this work, adding support
for templates for the web, desktop, liveview, ssr, and native-core renderers.
In the future we will try to shrink code generation, generally improve
performance, and simplify our implementation.
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