How can I set a fetchLimit dynamically for a SwiftUI @FetchRequest?

Question

I am using a FetchRequest in a chat app and want to set the fetchLimit dynamically. First I want to load 50 messages, then an additional number when the user scrolls to the top of the chat message list.

I am using the following code:

@FetchRequest private var messages: FetchedResults<Message>

private var predicate: NSPredicate
private var fetchLimit = 50
    
init(chatID: String) {
    
    self.predicate = NSPredicate(format: "chatID_ = %@", chatID)

    self._messages = FetchRequest(
        entity: Message.entity(),
        sortDescriptors: [
            NSSortDescriptor(keyPath: \Message.createdAt_, ascending: true),
        ],
        predicate: self.predicate
    )
}

How can I incorporate a fetchLimit into this which I can change dynamically?