src/main/java/com/github/jreddit/parser/util/CommentTreeUtils.java
private static void flattenCommentTree(List<CommentTreeElement> commentTree, List<CommentTreeElement> target) {
        for (CommentTreeElement c : commentTree) {
            target.add(c);
            if (c instanceof Comment) {
                flattenCommentTree(((Comment)c).getReplies(), target);
            }
        }
    }
private static void flattenCommentTree(List<CommentTreeElement> commentTree, List<CommentTreeElement> target) {
        for (CommentTreeElement c : commentTree) {
            target.add(c);
            if (c instanceof Comment) {
                flattenCommentTree(((Comment)c).getReplies(), target);
            }
        }
    }
Flatten the comment tree.
The original comment tree is not overwritten.

@param cs        List of comments that you get returned from one of the other methods here
@param target    List in which to place the flattened comment tree.