src/vs/workbench/api/common/extHostComments.ts/convertToCollapsibleState
function convertToCollapsibleState(kind: vscode.CommentThreadCollapsibleState | undefined): modes.CommentThreadCollapsibleState {
	if (kind !== undefined) {
		switch (kind) {
			case types.CommentThreadCollapsibleState.Expanded:
				return modes.CommentThreadCollapsibleState.Expanded;
			case types.CommentThreadCollapsibleState.Collapsed:
				return modes.CommentThreadCollapsibleState.Collapsed;
		}
	}
	return modes.CommentThreadCollapsibleState.Collapsed;
}