// Existing behaviour
$faker = Faker\Factory::create(); 
$faker->firstName(); // calling default provider : Faker\Provider\en_US\Person
$faker->addProvider(new Faker\Provider\zh_CN\Person($faker));
$faker->firstName(); // still calling the default provider because of this code https://github.com/FakerPHP/Faker/blob/d3c0752e756a387214c5b942cb7c5231d9bc8b64/src/Faker/Generator.php#L632

// What this PR does
$faker = Faker\Factory::create(); 
$faker->firstName(); // calling default provider : Faker\Provider\en_US\Person
$faker->addProvider(new Faker\Provider\zh_CN\Person($faker));
$faker->firstName(); // calling the new provider formatter