let sender_profile = {
            let txn = state.ndb.lookup_profile(nostr_event.pubkey)
            let profile = txn?.unsafeUnownedValue?.profile
            let picture = ((profile?.picture.map { URL(string: $0) }) ?? URL(string: robohash(nostr_event.pubkey)))!  // <-- Force unwrap error happens here
            return ProfileBuf(picture: picture,
                                 name: profile?.name,
                         display_name: profile?.display_name,
                                nip05: profile?.nip05)
        }()