/// <summary>
 /// Performs the action requested by the given XHR and returns an object to be applied
 /// on to the XHR (containing status, responseText, etc.). For the most part,
 /// this is delegated to doMethod methods on this class, such as doGet.
 /// </summary>
 /// <param name="xhr"><p>The simulated XMLHttpRequest instance.</p>
 /// </param>
 /// <returns>
 /// <span><see cref="Object">Object</see></span><div><p>The response properties to add to the XMLHttpRequest.</p>
 /// </div>
 /// </returns>
 public object exec(SimXhr xhr)
 {
     return(null);
 }
 /// <summary>
 /// Performs the action requested by the given XHR and returns an object to be applied
 /// on to the XHR (containing status, responseText, etc.). For the most part,
 /// this is delegated to doMethod methods on this class, such as doGet.
 /// </summary>
 /// <param name="xhr"><p>The simulated XMLHttpRequest instance.</p>
 /// </param>
 /// <returns>
 /// <span><see cref="Object">Object</see></span><div><p>The response properties to add to the XMLHttpRequest.</p>
 /// </div>
 /// </returns>
 public object exec(SimXhr xhr){return null;}