Performance & Efficiency rules

Ensure that `ThreadLocal` variables are cleaned using `.remove()` to avoid memory leaks.

Check that JSX list components have unique key properties. Missing keys can cause unnecessary re-renders and lead to state inconsistencies.

Check if React list keys are stable and unique. Using dynamic values like Math.random() or Date.now() can cause rendering issues. Recommend using unique IDs.

Check if resources such as files or database connections are properly closed in a `finally` block. This ensures resources are always released, even if an exception occurs.

Serve precompressed .br/.gz variants when the client sends Accept-Encoding, set "Vary: Accept-Encoding", and apply immutable caching for hashed assets; keep HTML revalidatable.

In Express, use serve-static with setHeaders to apply "Cache-Control: public, max-age=31536000, immutable" for files matching /\.[0-9a-f]{8,}\./ and "Cache-Control: no-cache" for HTML. Also set correct Content-Type.

Prefer Server Components for pages/layouts and move interactivity to small leaf Client Components. Only add 'use client' where browser APIs or event handlers are strictly necessary.

For dynamic data use { cache: 'no-store' } or file-level dynamic = 'force-dynamic'. For ISR use { next: { revalidate: N, tags: [...] } }.

Keep middleware fast and side-effect free (no DB writes). Narrow the matcher and skip static assets. Use Route Handlers for heavy logic.

Prefer JOINs/eager loading over per-row queries to avoid N+1 patterns.

Ensure LINQ queries translate to SQL efficiently (avoid client evaluation, use projections, defer ToList until needed).

Validate inputs and preconditions up-front and return early before issuing any database queries.

Use `for` elements inside map literals instead of `Map.fromIterable` to improve readability and allow better compiler optimizations.

Use `SizedBox` instead of `Container` when adding spacing in layouts to improve performance and avoid unnecessary rendering overhead.

Preload render-blocking WOFF2 fonts using <link rel="preload" as="font" type="font/woff2" crossorigin> and define @font-face with "font-display: swap". Only preload fonts used above the fold.

Ensure that `HashMap` and `HashSet` are initialized with appropriate capacity settings to optimize performance.

Do not send direct identifiers (email, CPF) to analytics. Use an HMAC-based pseudonymous ID derived from user ID and a rotating key; never reversible without server secret.

Identify cases where React Context values are being reassigned dynamically. Unstable context values trigger unnecessary re-renders. Use memoization to stabilize them.

Provide AVIF/WebP fallbacks via <img srcset> with width/height attributes, meaningful sizes, and "loading=lazy" plus "decoding=async". Avoid shipping oversized PNG/JPEG when AVIF/WebP is supported.

Every container must specify resources.requests and resources.limits for cpu and memory.

Ensure that `Arrays.stream(array)` is used instead of `Arrays.asList(T... a).stream()` for primitive arrays.

Ensure that all literal values passed to constructors of `@immutable` classes are marked as `const` to prevent unnecessary object creation.

Ensure that `entrySet()` is used instead of iterating over `keySet()` and calling `get(key)`, to optimize performance.

Detect code where resources (files, sockets, etc.) are not closed in a `finally` block. Using `finally` ensures that resources are released, even if an exception is raised.