Checks whether a username can be set for a new bot or assigned as a secondary username to an existing bot. Use
checkChatUsername to check username for other chat types.
Request type for Tdjson#checkBotUsername.
Pass true to check whether the username is suitable as a secondary username for an existing bot; pass false to check
whether the username is suitable for createBot.
Checks whether a username can be set for a new bot or assigned as a secondary username to an existing bot. Use checkChatUsername to check username for other chat types. Request type for Tdjson#checkBotUsername.