Firebase：类型“ StorageMetadata”的值没有成员“ downloadURLs”

Question

我似乎无法解决此问题，感谢您的提前帮助！ ：D （类型'StorageMetadata'的值没有成员'downloadURLs'）'

func sendMedia(picture: UIImage?) {
    guard let photo = picture else { return }
    print(picture)
    print(Storage.storage().reference())
    let filePath = "\(Auth.auth().currentUser!)/\(NSDate.timeIntervalSinceReferenceDate)"
    print(filePath)
    let data = photo.jpegData(compressionQuality: 0.1)
    let metadata = StorageMetadata()
    metadata.contentType = "image/jpg"
    Storage.storage().reference().child(filePath).putData(data!, metadata: metadata) { (metadata, error) in
        if error != nil {
            print(error?.localizedDescription)
            return
        }
        let fileURL = metadata!.downloadURLs![0].absoluteString
        let newMessage = self.messageRef.childByAutoId()
        let messageData = ["fileUrl": fileURL, "senderId": self.senderId, "senderName": self.senderDisplayName, "MediaType": "PHOTO"]
        newMessage.setValue(messageData)
    }
}

}