Created Retrieving all dialogs (markdown)

Retrieving-all-dialogs.md

@@ -0,0 +1,26 @@
+There are several `offset_xyz=` parameters that have no effect at all, but there's not much one can do since this is something the server should handle. Currently, the only way to get all dialogs (open chats, conversations, etc.) is by using the `offset_date`:
+
+```python
+from telethon.tl.functions.messages import GetDialogsRequest
+
+
+dialogs = []
+users = []
+chats = []
+
+last_date = None
+chunk_size = 20
+while True:
+    result = client.invoke(GetDialogsRequest(
+                 offset_date=last_date,
+                 offset_id=0,
+                 offset_peer=InputPeerEmpty(),
+                 limit=chunk_size
+             ))
+    dialogs.extend(result.dialogs)
+    users.extend(result.users)
+    chats.extend(result.chats)
+    last_date = min(msg.date for msg in result.messages)
+    if not result.dialogs:
+        break
+```