/// <summary>
 /// Overrides the message formatter used to provide the standard set of assertion failure messages.
 /// </summary>
 public static void Override(IFailureMessageFormatter newFormatter)
 {
     current = newFormatter;
 }
 /// <summary>
 /// Resets the current failure message formatter to the formatter.
 /// </summary>
 public static void Default()
 {
     current = null;
 }