React Performance: Server — After Non-blocking. Keywords: after non-blocking logging. Platform: React/Next.js. Description: Use Next.js after() to schedule work after response is sent. Do: Use after() for logging/analytics. Don't: Block response for non-critical operations. Good Example: after(async () => { await logAction() }); return Response.json(data). Bad Example: await logAction(); return Response.json(data). Severity: Medium.