IEnumerator DeleteProcess()
    {
        yield return(new WaitForEndOfFrame());

        Firebase.Storage.FirebaseStorage storage = Firebase.Storage.FirebaseStorage.DefaultInstance;
        // Create a storage reference from our storage service
        Firebase.Storage.StorageReference storage_ref = storage.GetReferenceFromUrl("gs://eduplatform-97d55.appspot.com/");
        // Create a reference to the file you want to upload
        Firebase.Storage.StorageReference rivers_ref = storage_ref.Child("ccc/" + fileName);                                                                         // 삭제하려는 파일의 레퍼런스...

        // Delete the file
        Task tmpTask = rivers_ref.DeleteAsync().ContinueWith(task => {
            if (task.IsCompleted)
            {
                Debug.Log("File deleted successfully.");
            }
            else
            {
                Debug.Log("error...");
            }
        });

        yield return(new WaitUntil(() => tmpTask.IsCompleted));

        PrintState("delete file complete");
    }