/// <summary>
/// Get an <see cref="OAuthRequestToken"/> for the given callback URL.
/// </summary>
/// <remarks>Specify 'oob' as the callback for no callback to be performed.</remarks>
/// <param name="callback">The callback Uri, or 'oob' if no callback is to be performed.</param>
/// <returns></returns>
public OAuthRequestToken OAuthGetRequestToken(string callback)
{
string url = "http://www.flickr.com/services/oauth/request_token";
Dictionary <string, string> parameters = OAuthGetBasicParameters();
parameters.Add("oauth_callback", callback);
string sig = OAuthCalculateSignature("POST", url, parameters, null);
parameters.Add("oauth_signature", sig);
string response = FlickrResponder.GetDataResponse(this, url, parameters);;
return(OAuthRequestToken.ParseResponse(response));
}