EventSource that emits an update every time the Live stream receives a new comment. You may
subscribe() to the
EventSource and provide it with a callback that takes a single argument; when the callback is called, this argument will have the properties
body (containing the text of the comment), and
timestampInVideoMs (containing the video timestamp in milliseconds at which the comment was submitted). The stream will only return comments that are displayed on the broadcaster's screen, which in the case of high comment volume will not include every comments. To process potentially large volumes of comments, use the Counter and Vote methods below.