method · iOS 17.0+nextTypeScriptnext(): Promise<(Array<GroupSessionJournal_Attachment>) | null>Swift declarationmutating func next() async -> GroupSessionJournal.Attachments.Element?Asynchronously advances to the next element and returns it, or ends the sequence if there is no next element. - Returns: The next element, if it exists, or `nil` to signal the end of the sequence.