src/Service/MailService.php
public function send($email, array $options = []): ResultInterface
    {
        // Try to resolve the email to be sent
        if (is_string($email)) {
            $email = $this->emailBuilder->build($email, $options);
        } elseif (is_array($email)) {
            $email = $this->emailBuilder->build(Email::class, $email);
        } elseif (! $email instanceof Email) {
            throw Exception\InvalidArgumentException::fromValidTypes(
                ['string', 'array', Email::class],
                $email,
                'email'
            );
        }

        // Trigger the pre render event and then render the email's body in case it has to be composed from a template
        $this->events->triggerEvent($this->createMailEvent($email, MailEvent::EVENT_MAIL_PRE_RENDER));
        $this->renderEmailBody($email);

        // Trigger pre send event, and cancel email sending if any listener returned false
        $eventResp = $this->events->triggerEvent($this->createMailEvent($email, MailEvent::EVENT_MAIL_PRE_SEND));
        if ($eventResp->contains(false)) {
            return new MailResult($email, false);
        }

        try {
            // Build the message object to send
            $message = MessageFactory::createMessageFromEmail($email)->setBody(
                $this->buildBody($email->getBody(), $email->getCharset())
            );
            $this->attachFiles($message, $email);
            $this->addCustomHeaders($message, $email);

            // Try to send the message
            $this->transport->send($message);

            // Trigger post send event
            $result = new MailResult($email);
            $this->events->triggerEvent($this->createMailEvent($email, MailEvent::EVENT_MAIL_POST_SEND, $result));
            return $result;
        } catch (Throwable $e) {
            // Trigger error event, notifying listeners of the error
            $this->events->triggerEvent($this->createMailEvent($email, MailEvent::EVENT_MAIL_SEND_ERROR, new MailResult(
                $email,
                false,
                $e
            )));

            throw new Exception\MailException('An error occurred while trying to send the email', $e->getCode(), $e);
        }
    }
public function send($email, array $options = []): ResultInterface
    {
        // Try to resolve the email to be sent
        if (is_string($email)) {
            $email = $this->emailBuilder->build($email, $options);
        } elseif (is_array($email)) {
            $email = $this->emailBuilder->build(Email::class, $email);
        } elseif (! $email instanceof Email) {
            throw Exception\InvalidArgumentException::fromValidTypes(
                ['string', 'array', Email::class],
                $email,
                'email'
            );
        }

        // Trigger the pre render event and then render the email's body in case it has to be composed from a template
        $this->events->triggerEvent($this->createMailEvent($email, MailEvent::EVENT_MAIL_PRE_RENDER));
        $this->renderEmailBody($email);

        // Trigger pre send event, and cancel email sending if any listener returned false
        $eventResp = $this->events->triggerEvent($this->createMailEvent($email, MailEvent::EVENT_MAIL_PRE_SEND));
        if ($eventResp->contains(false)) {
            return new MailResult($email, false);
        }

        try {
            // Build the message object to send
            $message = MessageFactory::createMessageFromEmail($email)->setBody(
                $this->buildBody($email->getBody(), $email->getCharset())
            );
            $this->attachFiles($message, $email);
            $this->addCustomHeaders($message, $email);

            // Try to send the message
            $this->transport->send($message);

            // Trigger post send event
            $result = new MailResult($email);
            $this->events->triggerEvent($this->createMailEvent($email, MailEvent::EVENT_MAIL_POST_SEND, $result));
            return $result;
        } catch (Throwable $e) {
            // Trigger error event, notifying listeners of the error
            $this->events->triggerEvent($this->createMailEvent($email, MailEvent::EVENT_MAIL_SEND_ERROR, new MailResult(
                $email,
                false,
                $e
            )));

            throw new Exception\MailException('An error occurred while trying to send the email', $e->getCode(), $e);
        }
    }
Tries to send the message, returning a MailResult object
@param string|array|Email $email
@param array $options
@return ResultInterface
@throws NotFoundExceptionInterface
@throws ContainerExceptionInterface
@throws Exception\InvalidArgumentException
@throws Exception\EmailNotFoundException
@throws Exception\MailException