Perf Is a 3× Median; Prefetch Comes as a Set with Skeletons
Sorting out lab-trace outliers, SSR prefetch query-key alignment, CLS skeleton reservation, and server-injected JSON-LD in one day
- A single dev-server Performance trace often has outliers, so before/after must be compared with the median of N reloads.
- SSR prefetch is a cache miss if the query key differs from the client by even one character, and it must be treated as a set with skeleton-height reservation, or CLS results.