public async Task <Root> GetForecast(string city, string state = null, string isoCountryCode = null)
{
if (string.IsNullOrWhiteSpace(city))
{
throw new ArgumentNullException(nameof(city), "City name must be provided");
}
state ??= _config.State;
isoCountryCode ??= _config.IsoCountryCode;
var url = _urlBuilder.BuildWeatherUrl(city, state, isoCountryCode);
var res = await _client.GetAsync(url);
if (!res.IsSuccessStatusCode)
{
throw new OpenWeatherClientException(res);
}
var jsonContent = await res.Content.ReadAsStringAsync();
return(JsonConvert.DeserializeObject <Root>(jsonContent));
}