if (\is_object($value)) {

                foreach ($classSerializers as $classSerializer) {
                   ...
                }

                if ($value instanceof \DateTimeInterface) {
                    return $this->serializeDate($value);
                }

    protected function serializeDate(\DateTimeInterface $date): string
    {
      $hasMicroseconds = $date->format("u") !== "000000";
      $formatted = $hasMicroseconds ? $date->format("Y-m-d H:i:s.u") : $date->format("Y-m-d H:i:s");
      $className = get_class($date);

      if ($date->getTimezone()) {
        // Also add timezone information
      }

      return "$className($formatted)";
    }