happening immediately in inglese:

an instantaneous response/reply/reaction

His reaction was instantaneous.

But with induction cooking the heat level is every bit as instantaneous—and as exact—as with gas, yet with none of the many drawbacks of gas (which we will detail later).

The effect would be instantaneous and painless. / In the real world you could meet someone you don't find attractive instantaneously and then get to know them and find that you do quite like them.