/// <summary>
 /// Get all declared data of type <c>T</c>.
 /// </summary>
 public static IEnumerable <T> All <T>(this ContextBuilder contextBuilder) where T : class
 {
     return(contextBuilder.DataStore.TypedData[typeof(T)].Select(o => o as T));
 }
 /// <summary>
 /// Get the last declared piece of data of type <c>T</c>.
 /// </summary>
 public static T Last <T>(this ContextBuilder contextBuilder) where T : class
 {
     return(contextBuilder.DataStore.TypedData[typeof(T)].Last() as T);
 }