The PageTitle API of TYPO3 CMS: how to use it in a ViewHelper?

ext_typoscript_setup.typoscript

config.pageTitleProviders {
    viewhelper {
        provider = My\Extension\PageTitle\ViewHelperPageTitleProvider
        before = altPageTitle
    }
}

TitleTagViewHelper.php

<?php

namespace My\Extension\ViewHelpers;

use Closure;
use My\Extension\PageTitle\ViewHelperPageTitleProvider;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3Fluid\Fluid\Core\Rendering\RenderingContextInterface;
use TYPO3Fluid\Fluid\Core\ViewHelper\AbstractViewHelper;
use TYPO3Fluid\Fluid\Core\ViewHelper\Traits\CompileWithRenderStatic;

/**
 * ViewHelper for <title> header tag
 * == Example ==
 *      <n:titleTag>{item.title}</n:titleTag>
 */
final class TitleTagViewHelper extends AbstractViewHelper
{
    use CompileWithRenderStatic;

    /**
     * Configure title through TitleProvider
     *
     * @param  array  $arguments
     * @param  \Closure  $renderChildrenClosure
     * @param  \TYPO3Fluid\Fluid\Core\Rendering\RenderingContextInterface  $renderingContext
     * @return void
     */
    public static function renderStatic(
        array $arguments,
        Closure $renderChildrenClosure,
        RenderingContextInterface $renderingContext
    ): void {
        $content = trim($renderChildrenClosure());

        if (!empty($content)) {
            GeneralUtility::makeInstance(ViewHelperPageTitleProvider::class)
                ->setTitle($content);
        }
    }
}

ViewHelperPageTitleProvider.php

<?php

namespace My\Extension\PageTitle;

use TYPO3\CMS\Core\PageTitle\AbstractPageTitleProvider;

/**
 * Used in config.pageTitleProviders
 */
final class ViewHelperPageTitleProvider extends AbstractPageTitleProvider
{
    /**
     * @param  string  $title
     * @return void
     */
    public function setTitle(string $title): void
    {
        $this->title = $title;
    }
}