Show resume progress bar from the middle

gdown/download.py

@@ -313,8 +313,9 @@ def download(
         tmp_file = None
         f = output
 
-    if tmp_file is not None and f.tell() != 0:
-        headers = {"Range": "bytes={}-".format(f.tell())}
+    start_size = f.tell()
+    if tmp_file is not None and start_size:
+        headers = {"Range": "bytes={}-".format(start_size)}
         res = sess.get(url, headers=headers, stream=True, verify=verify)
 
     if not quiet:
@@ -337,9 +338,9 @@ def download(
     try:
         total = res.headers.get("Content-Length")
         if total is not None:
-            total = int(total)
+            total = int(total) + start_size
         if not quiet:
-            pbar = tqdm.tqdm(total=total, unit="B", unit_scale=True)
+            pbar = tqdm.tqdm(total=total, unit="B", initial=start_size, unit_scale=True)
         t_start = time.time()
         for chunk in res.iter_content(chunk_size=CHUNK_SIZE):
             f.write(chunk)