Some.php

<?php

namespace Drupal\views\Plugin\views\pager;

use Drupal\Core\Form\FormStateInterface;

/**
 * Plugin for views without pagers.
 *
 * @ingroup views_pager_plugins
 *
 * @ViewsPager(
 *   id = "some",
 *   title = @Translation("Display a specified number of items"),
 *   help = @Translation("Display a limited number items that this view might find."),
 *   display_types = {"basic"}
 * )
 */
class Some extends PagerPluginBase {
    public function summaryTitle() {
        if (!empty($this->options['offset'])) {
            return $this->formatPlural($this->options['items_per_page'], '@count item, skip @skip', '@count items, skip @skip', [
                '@count' => $this->options['items_per_page'],
                '@skip' => $this->options['offset'],
            ]);
        }
        return $this->formatPlural($this->options['items_per_page'], '@count item', '@count items', [
            '@count' => $this->options['items_per_page'],
        ]);
    }
    protected function defineOptions() {
        $options = parent::defineOptions();
        $options['items_per_page'] = [
            'default' => 10,
        ];
        $options['offset'] = [
            'default' => 0,
        ];
        return $options;
    }
    
    /**
     * Provide the default form for setting options.
     */
    public function buildOptionsForm(&$form, FormStateInterface $form_state) {
        parent::buildOptionsForm($form, $form_state);
        $pager_text = $this->displayHandler
            ->getPagerText();
        $form['items_per_page'] = [
            '#title' => $pager_text['items per page title'],
            '#type' => 'number',
            '#min' => 0,
            '#description' => $pager_text['items per page description'],
            '#default_value' => $this->options['items_per_page'],
        ];
        $form['offset'] = [
            '#type' => 'number',
            '#min' => 0,
            '#title' => $this->t('Offset (number of items to skip)'),
            '#description' => $this->t('For example, set this to 3 and the first 3 items will not be displayed.'),
            '#default_value' => $this->options['offset'],
        ];
    }
    public function usePager() {
        return FALSE;
    }
    public function useCountQuery() {
        return FALSE;
    }
    public function query() {
        $this->view->query
            ->setLimit($this->options['items_per_page']);
        $this->view->query
            ->setOffset($this->options['offset']);
    }

}