'bar', 'foo' => 'foobar', ] ); echo 'Size : ' . $readOnlyCollection->count() . PHP_EOL; echo 'Foo = ' . $readOnlyCollection->get('Foo') . PHP_EOL; echo '-----' . PHP_EOL; $collection = new InsensitiveCaseKeyCollection($readOnlyCollection); $collection->add(28); echo 'Size : ' . $collection->count() . PHP_EOL;