我在XMPP的帮助下实现聊天功能，聊天工作正常。现在我正在上传图片，为此我上传图片到S3桶，上传图片到S3后，我使用XMPP方法将S3图片URL作为消息发送给其他用户。这也工作正常，但问题是它只工作，如果我留在同一屏幕上，即聊天屏幕时，图片上传。因此，如果我的图像仍在上传，我从视图控制器弹出，它被释放，我的完成处理程序没有得到调用后，上传图像到s3，因为我的sendMessage方法也没有得到调用。所以我怎么能做到这一点。我怎么能发送我的消息，并得到完成处理程序调用，即使我在不同的屏幕上，而图像上传。
这是我的代码挑选图像和上传图像

@IBAction func didPressMedia(_ sender: Any) {
        ImagePickerManager().pickImage(self) { \[weak self\] pickedImage in
        guard let self = self else { return }

        let compressedImage = pickedImage.resizedImage(newSize: CGSize(width: 120, height: 120))
        
        let messageId = XMPPHelper.shared.xmppStream.generateUUID

        let chat = ChatListModel()
        chat.roomId = ""
        chat.message = ""
        chat.messageId = messageId
        chat.time = String(Date().currentTimeMillis())
        chat.to = self.viewModel.otherUser
        chat.from = self.viewModel.myJid ?? ""
        chat.type = "chat/image"
        chat.imageLocalPath = messageId
        chat.msgDeliveryStatus = MsgDeliveryStatus.sending.rawValue
        chat.isSeenSync = true
        chat.isUploading = "pending"
        
        self.viewModel.setChatDataInRealm(item: chat, isAfterPickingImage: true)

        //This is completion handler which get called after image upload to s3.
        self.viewModel.didImageUploaded = { [weak self] isImgUploaded , imgUrl, imgMessageId in
            guard let self = self else { return }
            if isImgUploaded {
                print("success uploading image")
                self.viewModel.sendMessage(message: imgUrl, isImage: true, messageId: imgMessageId). // send image url as message to other user

            }else{
                print("error uploading image")
                self.viewModel.updateRealmAfterImageUpload(uploadStatus: "failed", uploadedUrl: "", messsageId: imgMessageId)
            }
        }

        self.viewModel.uploadImage(localPath: "\(Helper.shared.getDocumentDirectoryPath(filename: messageId)).png" ,image: compressedImage, messageId: messageId)
    }
}