(Try to) Fix calculating file size

src/workers.rs

@@ -612,14 +612,13 @@ pub async fn upload_worker(
         let total_size = file.seek(SeekFrom::End(0)).await.unwrap();
         file.seek(SeekFrom::Start(0)).await.unwrap();
         let parts = (total_size as f64 / (2000.0 * 1024.0 * 1024.0)).ceil() as usize;
-        let current_position = 0;
         for i in 0..parts {
             let filename = if parts == 1 {
                 video_filename.clone()
             } else {
                 format!("{}.part{:02}", &video_filename, i)
             };
-            let mut size = total_size - current_position;
+            let mut size = file.stream_position().await.unwrap();
             if size > 2000 * 1024 * 1024 {
                 size = 2000 * 1024 * 1024;
             }