addAll(iterable) {
		if (this._deopt) {
			const _set = this._set;
			for (const item of iterable) {
				_set.add(item);
			}
		} else {
			if (iterable instanceof LazySet) {
				if (iterable._isEmpty()) return this;
				this._toDeepMerge.push(iterable);
				this._needMerge = true;
				if (this._toDeepMerge.length > 100000) {
					this._flatten();
				}
			} else {
				this._toMerge.add(iterable);
				this._needMerge = true;
			}
			if (this._toMerge.size > 100000) this._merge();
		}
		return this;
	}
@param {Iterable<T> | LazySet<T>} iterable a immutable iterable or another immutable LazySet which will eventually be merged into the Set
@returns {LazySet<T>} itself