/// <summary>
/// Send HEAD request
/// </summary>
/// <param name="url">URL to request</param>
/// <param name="timeout">Current HTTP request timeout (default is 1 minute)</param>
/// <returns>HTTP request Task</returns>
public Task <HttpNetworkResponse> SendHeadRequestAsync(String url, TimeSpan?timeout = null)
{
return(SendRequestAsync(NetworkRequest.MakeHeadRequest(url), timeout));
}