1// Package webpush implements browser push delivery for the relay.2//3// Subscription validates an HTTPS endpoint, an uncompressed P-256 subscriber4// key and its 16-byte authentication secret. Keys stores the relay's P-2565// VAPID key and serializes it as unpadded base64url PKCS#8. Encrypt implements6// RFC 8291 aes128gcm payload encryption. Send builds the RFC 8292 VAPID7// authorization, posts the encrypted record, and reports whether the service8// accepted or retired the subscription.9package webpush