useKeyed
Runs a block of hooks inside a nested context that is rebuilt from scratch whenever the keys change. This is the primitive that lets you run hooks conditionally or per-item, which the plain rules of hooks forbid.
useIf
Runs a block of hooks only while a condition is true. It returns their result as T? - the value while the condition holds, null once it flips to false, at which point the inner hooks are disposed.
useMap
Runs the block once per key in a Set, giving each key its own nested hook context. The result is a Map from each key to that key's block result. It is the dynamic-set counterpart to useKeyed: where useKeyed keeps one keyed context, useMap keeps one per key.