Saving image file then uploading sometimes not working - dart

Question

So, I am trying to save an image file from the camera then upload it to firebase. Unfortunately, the firebase storage plugin has some errors and doesn't return errors in the catch so I need to check wifi connection before i do so, just in case i need to cache the image and upload it later. Once the image file has uploaded i then create some JSON and send that to firebase database where the app pulls down relevant information.
Note: sometimes this code works and the image is not empty, othertimes the image comesback empty so im guessing its a timing issue?
Future saveImageFile(UploadImage image) async {
await storage.init();
var imageFile = storage.saveImageFile(image.file, image.getName());
instance.setInt("ImageCount", imageCount + 1);
checkConnectionThenUploadImage(imageFile);
}
//From storage class
File saveImageFile(File toBeSaved, String fileName) {
final filePath = '$imageDirectory$fileName';
var file = new File(filePath)
..createSync(recursive: true)
..writeAsBytes(toBeSaved.readAsBytesSync());
return file;
}
checkConnectionThenUploadImage(File image) {
checkConnectivity().then((isConnected) async {
if (!isConnected) {
instance.setBool("hasImagesToUpload", true);
} else {
await saveImageToStorage(image);
}
}).catchError((error) {
print("Error getting connectivity status, was error: $error");
});
}
saveImageToStorage(File imageFile) async {
final fileName = getNameFromFile(imageFile);
final StorageReference ref = FirebaseStorage.instance.ref().child("AllUsers").child(uuid).child(fileName);
final StorageUploadTask uploadTask = ref.putFile(imageFile, const StorageMetadata(contentLanguage: "en"));
final url = (await uploadTask.future).downloadUrl;
if (url != null) { //Normally you could catch an error here but the plugin has a bug so it needs to be checked in other ways
final fireImage = new FireImage(getNameFromFile(imageFile), storage.getDateFromFileName(fileName), imageCount, "", url.toString());
saveImageJsonToDatabase(fireImage);
storage.deleteImageFile(fileName);
} else {
checkConnectionThenUploadImage(imageFile);
}
}
saveImageJsonToDatabase(FireImage image) async {
await storage.init();
storage.saveJsonFile(image);
checkConnectivity().then((isConnected) {
if (!isConnected) {
instance.setBool("hasJsonToUpload", true);
} else {
final DatabaseReference dataBaseReference = FirebaseDatabase.instance.reference().child("AllUsers").child(uuid);
dataBaseReference.child("images").push().set(image.toJson()).whenComplete (() {
storage.deleteJsonFile(basename(image.name));
}).catchError((error) { //catching errors works with firebase database
saveImageJsonToDatabase(image);
});
}
});
}
//From storage class
deleteImageFile(String fileName) async {
final filePath = '$imageDirectory$fileName';
File(filePath).delete();
}
The image gets uploaded and the json is created but when i try to view the image using the download url from firebase storage it says the image is empty. The only clue i have is that this is a timing issue because it only happens occasionally.
Can anyone see where im going wrong?