/// <summary>
 /// Adds a key to the table.
 /// </summary>
 /// <param name="key">The key to add. key represents the object to which the property is attached.</param>
 /// <param name="value">The key's property value.</param>
 public void Add(TKey key, TValue value)
 {
     if (key == null)
     {
         throw new ArgumentNullException("key");
     }
     _wrapped.AddNew(key, value);
 }