true if the browser reports "online" (fallback-only behavior if Network Info API is missing).
Optional
typee.g., "wifi" | "cellular" | "ethernet" | "none" (normalized best-effort).
Optional
effectivee.g., "slow-2g" | "2g" | "3g" | "4g" (per Network Info API).
Optional
downlinkApprox downstream bandwidth in megabits/sec when available.
Optional
rttRound-trip time estimate in ms when available.
Optional
saveWhether the user enabled "Data Saver" / reduced data mode.
Snapshot of client network conditions, normalized across browsers.