New realtime sdk methods and working

[ArnabChatterjee20k]

What does this PR do?

realtime = new Realtime()
sub1 = realtime.subscribe()
sub2 = realtime.subscribe()

// for unsubscribing only sub1
sub1.unsubscribe() // earlier it would disconnect the whole client
sub2.unsubscribe() // only sub2

// update
sub1.update({channels:[], queries:[]})

// disconnect the whole client
realtime.disconnect() // typically during the component unmount

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[greptile-apps]

Greptile Summary

This PR replaces the slot-based subscription-ID reconciliation model with client-generated UUIDs across web, Flutter, Android, and Apple SDK templates, and adds unsubscribe(), update(), and disconnect() as first-class methods on the subscription object.

• React Native not updated: templates/react-native/src/client.ts.twig is in the changeset but subscribe() still returns a bare () => void with the old slotToSubscriptionId/pendingSubscribeSlots internals — the new unsubscribe, update, and disconnect API is absent for React Native consumers.
• Android lock held across ws.send(): In Realtime.kt.twig, sendPendingSubscribes() is called inside synchronized(subscriptionLock) in subscribe(), causing ws.send() to execute while the lock is held — a potential deadlock with OkHttp's IO-thread callbacks that also acquire subscriptionLock.

Confidence Score: 4/5

Safe to merge after the Android lock scope and React Native gaps are resolved.

Two P1 findings remain: the React Native template missing the new API entirely, and the Android subscribe() holding subscriptionLock across ws.send() which is a latent deadlock. The core redesign is sound across web, Flutter, Apple, and Android listener paths.

templates/react-native/src/client.ts.twig (missing new API) and templates/android/library/src/main/java/io/package/services/Realtime.kt.twig (lock held across ws.send).

Important Files Changed

Filename	Overview
templates/react-native/src/client.ts.twig	subscribe() still returns () => void using the old slot-based model — missing the new unsubscribe/update/disconnect API that was added to every other platform in this PR.
templates/android/library/src/main/java/io/package/services/Realtime.kt.twig	Switches to client-generated subscriptionIds with LinkedHashMap pending queue; sendPendingSubscribes called inside the lock in subscribe() causing ws.send() to execute while the lock is held.
templates/apple/Sources/Services/Realtime.swift.twig	Migrated to client-side subscriptionIds; update closure calls DispatchQueue.sync inside an async context which can block the Swift cooperative thread pool; logic otherwise well-structured.
templates/flutter/lib/src/realtime_mixin.dart.twig	Adds unsubscribe/update/close to RealtimeSubscription; _createSocket still computes allChannels set just to check emptiness; overall logic is correct.
templates/web/src/services/realtime.ts.twig	Complete redesign using client-generated subscriptionIds; adds unsubscribe/update/disconnect with debounce logic; pendingSubscribes.clear() precedes socket.send() but reconnect re-enqueue mitigates silent drops.
templates/flutter/lib/src/realtime_subscription.dart.twig	Adds unsubscribe, update, and close fields; clean data class with correct documentation.
templates/android/library/src/main/java/io/package/models/RealtimeModels.kt.twig	Adds RealtimeSubscriptionUpdate and unsubscribe/update fields to RealtimeSubscription; channels typed as Collection to accept both String and Channel objects.
templates/swift/Sources/Models/RealtimeModels.swift.twig	Adds RealtimeSubscriptionUpdate and RealtimeSubscription classes with unsubscribe/update/close async actions; clean implementation.

Comments Outside Diff (1)

1. templates/react-native/src/client.ts.twig, line 513-540 (link)

   React Native subscribe still returns the old () => void teardown — missing unsubscribe, update, and disconnect

   Every other platform in this PR (web, Flutter, Android, Apple) now returns a RealtimeSubscription object with unsubscribe(), update(), and close() methods, plus a top-level disconnect(). The React Native template was included in the changeset but its subscribe() still returns a bare () => void closure backed by the old slotToSubscriptionId / subscriptionIdToSlot maps. React Native consumers cannot call sub.unsubscribe() or sub.update({channels, queries}) as described in the PR.

   The Realtime type defined inside the file (lines 108–140) also still references pendingSubscribeSlots, slotToSubscriptionId, and subscriptionIdToSlot — the slot-based model that was replaced everywhere else.

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