The discussion of a GitHub issue (or pull request) as mmo.client's <mmo-kanban> shows it: comments with their author, which can answer one another.
class MMO\git\helpers\IssueDiscussion
Namespace
MMO\git\helpers
GitHub's comments are flat: a reply is a comment that starts with a comment of its own, which GitHub does not
show, naming the one it answers, and a quote of it, which GitHub shows:
```markdown
<!-- mmo-kanban reply-to:2165473 -->
> [@marc](https://github.com/owner/name/issues/12#issuecomment-2165473) wrote:
> The first line of what it answers…
The reply.
```
The board shows the reply under what it answers, without the quote; github.com shows it in its place by date,
with the quote saying what it answers.
$discussion = new IssueDiscussion(GitHubAPI::Shared(), 'owner/name', 12);
$first = $discussion->add('Is this still happening?');
$discussion->add('Yes, on 2.1.', $first['id']);