buildAttachments example

'content' => 'foo',
                    'fileName' => 'foo',
                    'mimeType' => 'foo',
                ],
                [
                    'content' => 'bar',
                    'fileName' => 'bar',
                    'mimeType' => 'bar',
                ]
            );

        $attachments = $this->attachmentsBuilder->buildAttachments($context, $mailTemplate, $extension, [], Uuid::randomHex());

        static::assertEquals(
            [
                [
                    'content' => 'foo',
                    'fileName' => 'foo',
                    'mimeType' => 'foo',
                ],
                [
                    'content' => 'bar',
                    'fileName' => 'bar',
                    

$mimeType = null;
            }
            $message->attach($this->filesystem->read($url) ?: '', basename($url), $mimeType);
        }

        $config = $message->getMailAttachmentsConfig();

        if (!$config) {
            return $this->decorated->send($message, $envelope);
        }

        $attachments = $this->attachmentsBuilder->buildAttachments(
            $config->getContext(),
            $config->getMailTemplate(),
            $config->getExtension(),
            $config->getEventConfig(),
            $config->getOrderId()
        );

        foreach ($attachments as $attachment) {
            $message->attach(
                $attachment['content'],
                $attachment['fileName'],