500 error from server side via sending message with mention in thread

[Nikitos9I]

Hello!

I try to use this combo of methods:

1. send file to channel with

SlackMessageHandle<SlackMessageReply> sendFile(SlackChannel channel, byte [] data, String fileName, String title, String initialComment);

2. open thread for this message with file and mention user group with methods:

SlackPreparedMessage slackPreparedMessage = new Builder().withMessage(message).withLinkNames(true).withThreadTimestamp(messageHandle.getReply().getTimestamp()).build();
session.sendMessage(session.findChannelByName(channelName), slackPreparedMessage);

3. I get 500 error

{
  "timestamp": "2019-09-06T14:48:24.400+0000",
  "status": 500,
  "error": "Internal Server Error",
  "message": "class com.ullink.slack.simpleslackapi.replies.SlackReplyImpl cannot be cast to class com.ullink.slack.simpleslackapi.replies.SlackMessageReply (com.ullink.slack.simpleslackapi.replies.SlackReplyImpl and com.ullink.slack.simpleslackapi.replies.SlackMessageReply are in unnamed module of loader 'app')",
  "path": "/start/notify"
}

Please, fix this! I need to implement this case in my product! Thanks a lot!

[Nikitos9I]

@bcorne could you please look at this issue