src/vs/workbench/api/common/extHostTypes.ts/TerminalLink/constructor
class TerminalLink:	constructor(
		public startIndex: number,
		public length: number,
		public tooltip?: string
	) {
		if (typeof startIndex !== 'number' || startIndex < 0) {
			throw illegalArgument('startIndex');
		}
		if (typeof length !== 'number' || length < 1) {
			throw illegalArgument('length');
		}
		if (tooltip !== undefined && typeof tooltip !== 'string') {
			throw illegalArgument('tooltip');
		}
	}