public void CheckUsernameAsync(TLString username, Action <TLBool> callback, Action <TLRPCError> faultCallback = null)
        {
            var obj = new TLCheckUsername {
                Username = username
            };

            SendInformativeMessage("account.checkUsername", obj, callback, faultCallback);
        }
        public void CheckUsernameAsync(TLInputChannelBase channel, TLString username, Action <TLBool> callback, Action <TLRPCError> faultCallback = null)
        {
            var obj = new TLCheckUsername {
                Channel = channel, Username = username
            };

            SendInformativeMessage("channels.checkUsername", obj, callback, faultCallback);
        }