* multimap.put(key2, bar);
 * multimap.put(key1, baz);
 * }</pre>
 *
 * ... the iteration order for {@link #keys()} is {@code [key1, key2, key1]}, and similarly for
 * {@link #entries()}. Unlike {@link LinkedHashMultimap}, the iteration order is kept consistent
 * between keys, entries and values. For example, calling:
 *
 * <pre>{@code
 * multimap.remove(key1, foo);
 * }</pre>
 *