take(maxTakeCount) {
        if (maxTakeCount < 0) {
            throw new Error("needed maxTakeCount >= 0");
        }
        if (maxTakeCount === 0) {
            return new Seq([]);
        }
        let seq = this._iterable;
        return Seq.fromGenerator(function*() {
            let i = 0;
            for (let e of seq) {
                yield e;
                i++;
                if (i >= maxTakeCount) {
                    break;
                }
            }
        });
    }
Returns a sequence with the same items, except cut short if it exceeds the given maximum count.
@param {!int} maxTakeCount
@returns {!Seq.<T>}
@template T