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    <h3>Editing: AbstractTransport.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Mailer\Transport;

use Psr\EventDispatcher\EventDispatcherInterface;
use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;
use Symfony\Bridge\Twig\Mime\TemplatedEmail;
use Symfony\Component\Mailer\Envelope;
use Symfony\Component\Mailer\Event\FailedMessageEvent;
use Symfony\Component\Mailer\Event\MessageEvent;
use Symfony\Component\Mailer\Event\SentMessageEvent;
use Symfony\Component\Mailer\Exception\LogicException;
use Symfony\Component\Mailer\SentMessage;
use Symfony\Component\Mime\Address;
use Symfony\Component\Mime\BodyRendererInterface;
use Symfony\Component\Mime\RawMessage;

/**
 * @author Fabien Potencier &lt;fabien@symfony.com&gt;
 */
abstract class AbstractTransport implements TransportInterface
{
    private ?EventDispatcherInterface $dispatcher;
    private LoggerInterface $logger;
    private float $rate = 0;
    private float $lastSent = 0;

    public function __construct(EventDispatcherInterface $dispatcher = null, LoggerInterface $logger = null)
    {
        $this-&gt;dispatcher = $dispatcher;
        $this-&gt;logger = $logger ?? new NullLogger();
    }

    /**
     * Sets the maximum number of messages to send per second (0 to disable).
     *
     * @return $this
     */
    public function setMaxPerSecond(float $rate): static
    {
        if (0 &gt;= $rate) {
            $rate = 0;
        }

        $this-&gt;rate = $rate;
        $this-&gt;lastSent = 0;

        return $this;
    }

    public function send(RawMessage $message, Envelope $envelope = null): ?SentMessage
    {
        $message = clone $message;
        $envelope = null !== $envelope ? clone $envelope : Envelope::create($message);

        try {
            if (!$this-&gt;dispatcher) {
                $sentMessage = new SentMessage($message, $envelope);
                $this-&gt;doSend($sentMessage);

                return $sentMessage;
            }

            $event = new MessageEvent($message, $envelope, (string) $this);
            $this-&gt;dispatcher-&gt;dispatch($event);
            $envelope = $event-&gt;getEnvelope();
            $message = $event-&gt;getMessage();

            if ($message instanceof TemplatedEmail &amp;&amp; !$message-&gt;isRendered()) {
                throw new LogicException(sprintf('You must configure a &quot;%s&quot; when a &quot;%s&quot; instance has a text or HTML template set.', BodyRendererInterface::class, get_debug_type($message)));
            }

            $sentMessage = new SentMessage($message, $envelope);

            try {
                $this-&gt;doSend($sentMessage);
            } catch (\Throwable $error) {
                $this-&gt;dispatcher-&gt;dispatch(new FailedMessageEvent($message, $error));
                $this-&gt;checkThrottling();

                throw $error;
            }

            $this-&gt;dispatcher-&gt;dispatch(new SentMessageEvent($sentMessage));

            return $sentMessage;
        } finally {
            $this-&gt;checkThrottling();
        }
    }

    abstract protected function doSend(SentMessage $message): void;

    /**
     * @param Address[] $addresses
     *
     * @return string[]
     */
    protected function stringifyAddresses(array $addresses): array
    {
        return array_map(function (Address $a) {
            return $a-&gt;toString();
        }, $addresses);
    }

    protected function getLogger(): LoggerInterface
    {
        return $this-&gt;logger;
    }

    private function checkThrottling()
    {
        if (0 == $this-&gt;rate) {
            return;
        }

        $sleep = (1 / $this-&gt;rate) - (microtime(true) - $this-&gt;lastSent);
        if (0 &lt; $sleep) {
            $this-&gt;logger-&gt;debug(sprintf('Email transport &quot;%s&quot; sleeps for %.2f seconds', __CLASS__, $sleep));
            usleep($sleep * 1000000);
        }
        $this-&gt;lastSent = microtime(true);
    }
}
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