I want to show "show more" in slack messages.
I use the slack web api to send messages. If the number of characters is long, I want to use the "show more" button.
What I've found so far is using the text field of secondary message attachments. But since this is legacy, they tell me to use the block kit, but I don't know how. (https://api.slack.com/reference/messaging/attachments)
Is there any way?