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     */
    public function findOne($filter = [], array $options = [])
    {
        if ( ! isset($options['readPreference'])) {
            $options['readPreference'] = $this->readPreference;
        }

        $server = $this->manager->selectServer($options['readPreference']);

        if ( ! isset($options['readConcern']) && \MongoDB\server_supports_feature($server, self::$wireVersionForReadConcern)) {
            $options['readConcern'] = $this->readConcern;
        }