InvoiceCommentSender.php

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
namespace Magento\Sales\Model\Order\Email\Sender;

use Magento\Sales\Model\Order;
use Magento\Sales\Model\Order\Email\Container\InvoiceCommentIdentity;
use Magento\Sales\Model\Order\Email\Container\Template;
use Magento\Sales\Model\Order\Email\NotifySender;
use Magento\Sales\Model\Order\Invoice;
use Magento\Sales\Model\Order\Address\Renderer;
use Magento\Framework\Event\ManagerInterface;
use Magento\Framework\DataObject;

/**
 * Class InvoiceCommentSender
 */
class InvoiceCommentSender extends NotifySender
{
    /**
     * @var Renderer
     */
    protected $addressRenderer;

    /**
     * Application Event Dispatcher
     *
     * @var ManagerInterface
     */
    protected $eventManager;

    /**
     * @param Template $templateContainer
     * @param InvoiceCommentIdentity $identityContainer
     * @param Order\Email\SenderBuilderFactory $senderBuilderFactory
     * @param \Psr\Log\LoggerInterface $logger
     * @param Renderer $addressRenderer
     * @param ManagerInterface $eventManager
     */
    public function __construct(
        Template $templateContainer,
        InvoiceCommentIdentity $identityContainer,
        \Magento\Sales\Model\Order\Email\SenderBuilderFactory $senderBuilderFactory,
        \Psr\Log\LoggerInterface $logger,
        Renderer $addressRenderer,
        ManagerInterface $eventManager
    ) {
        parent::__construct($templateContainer, $identityContainer, $senderBuilderFactory, $logger, $addressRenderer);
        $this->addressRenderer = $addressRenderer;
        $this->eventManager = $eventManager;
    }

    /**
     * Send email to customer
     *
     * @param Invoice $invoice
     * @param bool $notify
     * @param string $comment
     * @return bool
     */
    public function send(Invoice $invoice, $notify = true, $comment = '')
    {
        $order = $invoice->getOrder();
        $this->identityContainer->setStore($order->getStore());

        $transport = [
            'order' => $order,
            'invoice' => $invoice,
            'comment' => $comment,
            'billing' => $order->getBillingAddress(),
            'store' => $order->getStore(),
            'formattedShippingAddress' => $this->getFormattedShippingAddress($order),
            'formattedBillingAddress' => $this->getFormattedBillingAddress($order),
        ];
        $transportObject = new DataObject($transport);

        /**
         * Event argument `transport` is @deprecated. Use `transportObject` instead.
         */
        $this->eventManager->dispatch(
            'email_invoice_comment_set_template_vars_before',
            ['sender' => $this, 'transport' => $transportObject->getData(), 'transportObject' => $transportObject]
        );

        $this->templateContainer->setTemplateVars($transportObject->getData());

        return $this->checkAndSend($order, $notify);
    }
}