/// <summary>
/// Wraps this <see cref="HoconValue" /> into a new <see cref="HoconObject" /> at the specified key.
/// </summary>
/// <param name="key">The key designated to be the new root element.</param>
/// <returns>A new HOCON root.</returns>
/// <remarks>
/// Immutable. Performs a deep copy on this <see cref="HoconValue" /> first.
/// </remarks>
public HoconRoot AtKey(string key)
{
var value = new HoconValue(null);
var obj = new HoconObject(value);
var field = new HoconField(key, obj);
field.SetValue(Clone(field) as HoconValue);
obj.Add(key, field);
value.Add(obj);
return(new HoconRoot(value));
}