public HttpRequest query(string parameter, string value = null)
{
var url = new UriBuilder(this.URL);
var newQueryString = new FormUrlEncodedContent(new Dictionary <string, string>
{
{ parameter, value }
}).ReadAsStringAsync().Result;
if (value == null)
{
newQueryString = newQueryString.Substring(0, newQueryString.Length - 1);
}
if (url.Query == "")
{
url.Query = newQueryString;
}
else
{
url.Query = string.Join("&", url.Query.Substring(1), newQueryString);
}
URL = url.Uri;
return(this);
}