skip(maxSkipCount) {
        if (maxSkipCount < 0) {
            throw new Error("needed maxSkipCount >= 0");
        }
        if (maxSkipCount === 0) {
            return this;
        }

        let seq = this._iterable;
        return Seq.fromGenerator(function*() {
            let i = 0;
            for (let e of seq) {
                if (i >= maxSkipCount) {
                    yield e;
                }
                i++;
            }
        });
    }
Returns a sequence with the same items, except the give number are skipped at the start.
@param {!int} maxSkipCount
@returns {!Seq.<T>}
@template T