setActualEffectToUpdateFunc(circuitUpdateFunc) {
        if (circuitUpdateFunc !== undefined && typeof circuitUpdateFunc !== "function") {
            throw new DetailedError("Bad customOperation", {circuitUpdateFunc});
        }
        this.gate.customOperation = circuitUpdateFunc;
        return this;
    }
Sets a custom circuit-update function to run when simulating this gate.
@param {undefined|!function(!CircuitEvalContext)} circuitUpdateFunc
@returns {!GateBuilder}