带类的数组：检查唯一性

I have a collection of classes, and I need to filter them whether they're unique in an array.

My approach:

public function unique() {
    $uniqueStreams = [];

    foreach($this->streams as $stream) {
        if(!in_array($stream, $uniqueStreams)) {
            $uniqueStreams[] = $stream;
        }
    }

    return new static($uniqueStreams);
}

The problem is, that in_array only checks for the existance of that classname(at least that's what I've explored), but I need to make sure that they're not identical(it is desired that the instances are from the same class).

As @u_mulder turned out, serializing them and compare the strings is solving the challenge!

public function unique() {
    $uniqueStreams = [];

    foreach($this->streams as $stream) {
        $serialized = serialize($stream);
        if(!in_array($serialized, $uniqueStreams)) {
            $uniqueStreams[] = $serialized;
        }
    }

    foreach($uniqueStreams as &$uniqueStream) {
        $uniqueStream = unserialize($uniqueStream);
    }

    return new static($uniqueStreams);
}