* directly if required. While URI escapers impose specific semantics on which characters are
 * considered 'safe', this class has a minimal set of restrictions.
 *
 * <p>When escaping a String, the following rules apply:
 *
 * <ul>
 *   <li>All specified safe characters remain unchanged.
 *   <li>If {@code plusForSpace} was specified, the space character " " is converted into a plus
 *       sign {@code "+"}.