Where is the FADE effect in audio?

Hi, why doesn't the "fade" effect exist in the audio plugin?

It is a very basic effect on the reproduction of sounds, however, it cannot be applied at runtime.

I refer to the effect of initial automatic volume increase (fade in) when a song or FX plays and the automatic volume decrease (fade out) at the end of the track or FX.

Am I missing something or can this effect really not apply?

Soundtrack set volume to VOL

if audiofade = 1

set VOL to VOL-1

if VOL < -100 set audiofade to 0

There you go, faster than adding and setting up the actual plugin