code: func NewClientWithCustomHttpConfig(apiKey, apiSecret string, httpClient *http.Client) (c *client) {
  	timeout := httpClient.Timeout
  	if timeout <= 0 {
  		timeout = 30 * time.Second
  	}
  	return &client{apiKey, apiSecret, httpClient, timeout, false}
  }
docs: // NewClientWithCustomHttpConfig returns a new Bittrex HTTP client using the predefined http client