[BUG] azure-communication-email:1.1.0-beta.1 - cannot send email with attachments

[ejossev]

Describe the bug
Cannot send email with attachments with version 1.1 beta1

Exception or Stack Trace
The error I'm getting back is:
Status code 400, "{"error":{"code":"BadRequest","message":"Request body validation error. ContentBytes invalid. Should be base64.","target":null,"details":null,"innererror":null}}"

To Reproduce
Try to send the mail with attachments, see code below.

Code Snippet

@Service
public class AzureMailService implements MessagingService {
    @Autowired
    public AzureMailService(
            @Value("${ch.hygiaso.azure-email.connection-string}")
            String connectionString,
            @Value("${ch.hygiaso.azure-email.sender-address}")
            String senderAddress
    ) {
        emailClient = new EmailClientBuilder()
                .connectionString(connectionString)
                .buildAsyncClient();
        this.senderAddress = senderAddress;
    }

    public void sendMessage(String recipientAddress, String subject, String body, FileContentDTO... attachments) {
        logger.debug("Sending notification email to {}", recipientAddress);
        EmailMessage message = new EmailMessage()
                .setSenderAddress(senderAddress)
                .setToRecipients(recipientAddress)
                .setSubject(subject)
                .setBodyHtml(body)
                .setAttachments(Arrays.stream(attachments).map(att -> new EmailAttachment(att.getName(), att.getContentType(), BinaryData.fromBytes(att.getContent()))).toList());
        var poller = emailClient.beginSend(message);
        poller.subscribe(response -> {
                    if (response.getStatus() == LongRunningOperationStatus.SUCCESSFULLY_COMPLETED) {
                        logger.trace("Successfully sent the email (operation id: {})", response.getValue().getId());
                    }
                },
                error -> logger.error("Error occurred while sending email to {}: {}", anonymizeEmailForLogging(recipientAddress), error.getMessage()));
        logger.debug("Email queued for sending");
    }
}

Expected behavior
E-mail is queued

Screenshots
N/A

Setup (please complete the following information):

• OS: Azure web apps - no clue what is running there
• IDE: N/A
• Library/Libraries: com.azure:azure-communication-email:1.1.0-beta.1
• Java version: 17
• App Server/Environment: Azure web apps
• Frameworks: spring boot

Additional context
Works well with 1.0.18. I want to upgrade to 1.1 version to be able to set CID and refer images from the html content, but pure change of the package version causes this issue.

Information Checklist