nextIteration() {
        if (this.contexts && this.contexts.length > 0) {
            this.contexts = this.contexts.slice();
            this.lastId++;
            const context = Object.assign({}, this.contexts[this.contexts.length - 1]);
            context.iterationId += 1;
            context.id = this.lastId;
            this.contexts.splice(-1, 1, context);
            this._currentContextIds.splice(0, 1, this.contextIdforContexts(this.contexts));
        } else throw new Error("Cannot increase frame iteration, the context is empty");
    }
Enter the next iteration of a loop, the iteration id of last context is
increased.