public virtual Boolean TryAdd([NotNull] TKey key, [NotNull] TValue value)
{
if (key is null)
{
throw new ArgumentNullException(nameof(key));
}
if (value is null)
{
throw new ArgumentNullException(nameof(value));
}
if (ContainsKey(key) || ContainsValue(value))
{
return(false);
}
Boolean added = Base.TryAdd(key, value);
if (added ^ Reversed.TryAdd(value, key))
{
throw new CollectionSyncException();
}
return(added);
}