Add temporary experimental delay to check hypothesis on occasional init timeline staleness

Signed-off-by: Daniel D’Aquino <daniel@daquino.me>

damus/Core/Networking/NostrNetworkManager/SubscriptionManager.swift

@@ -197,6 +197,14 @@ extension NostrNetworkManager {
                         try await Task.sleep(nanoseconds: 1_000_000_000)
                         continue
                     }
+                    
+                    // FIXME: The delay below is to prevent race conditions when the RelayPool is initializing during the app start.
+                    // Without this, occasionally there is a race condition that causes the subscribe call to be missed somehow
+                    // despite mechanisms in place to queue up requests when relays are disconnected, as well as mechanisms to send subscribe requests when the relay is already connected.
+                    // This is difficult to fix as it will require a big refactor in `RelayPool` to implement proper async/await mechanisms, instead of the current "fire and forget" interfaces.
+                    // If this delay fixes the occasional timeline staleness when starting the app, it helps prove the hypothesis above.
+                    try await Task.sleep(nanoseconds: 2_000_000_000)
+                    
                     do {
                         for await item in self.pool.subscribe(filters: filters, to: desiredRelays, id: id) {
                             // NO-OP. Notes will be automatically ingested by NostrDB