Feature request: Gates: separate `Threshold` for `Attack` and `Release`

[LebedevRI]

EasyEffects Gate/Multiband Gate uses Calf Studio Gear-provided Gate:
https://github.com/wwmm/easyeffects/blob/262d427d6722788840f1a26d982ea1067cffab54/src/gate.cpp

I would have liked to see if having separate Thresholds for the Attack and the Release times
would lead to better gating results, in particular, by having high Attack threshold (-24dB?),
but low Release threshold (-48dB?), but unfortunately there is only a single Threshold.

With a single threshold, i need to either set it low, but then it's more susceptible to unintentional activation,
or high, but then it may gate things too well.