/// <summary>
 /// If the key exists, calls BaseRemove on it.
 /// </summary>
 public void Remove(ExpiredKey mapping)
 {
     if (BaseIndexOf(mapping) >= 0)
     {
         BaseRemove(mapping.Key);
     }
 }
 /// <summary>
 /// Calls BaseAdd.
 /// </summary>
 public void Add(ExpiredKey mapping)
 {
     BaseAdd(mapping);
 }
 /// <summary>
 /// Calls BaseIndexOf on the given <see cref="ExpiredKey" />.
 /// </summary>
 public int IndexOf(ExpiredKey encryptionKey)
 {
     return(BaseIndexOf(encryptionKey));
 }