Hi., i'm working on a prototype application (winforms) since this morning, due to less documentation. Now i created a sample application (winforms) which successfully loads all the contacts from the authenticated registered user on Telegram. It is somehow difficult to place a timer for delivery duration information of auth code since there is no functionality available on the api. On my sample app, first the user enters apiid, apihash and phone number and click connect then a dialog will be show to enter the auth code sent to the Telegram desktop app. After successful connection the app loads the contacts in a listbox. User selects a contact then enter message and hit the send button. Then the message will be delivered to the selected contact. I tested it, ping me so that i can send the app and you can test it.