/// <summary>
/// Append a string to the list.
/// </summary>
/// <param name="str">The <c>string</c> to append.</param>
public void Append(string str)
{
#if USE_LIBCURLSHIM
Handle = NativeMethods.curl_shim_add_string_to_slist(Handle, str);
#else
Handle = NativeMethods.curl_slist_append(Handle, str);
#endif
}