Threshold with smooth edge (similar to Step A<=B)

Hello!

I'd like to see a bit more advanced variant of the threshold node (like Step A<=B node (well probably called something else), with "smoothing distance" input. Instead of sharp transition, it would allow to smoothly lerp between 0 and 1 over the threshold edge by a given distance, centered around the edge.

For example for inputs:
B = 0.4
Distance = 0.1
It would output following for given range of A

A = -Inf to 0.3 => Outputs 1.0
A = 0.3 to 0.5 => Lerps from 1.0 to 0.0
A = 0.5 to inf => Outputs 0.0 

I usually do this with a combination of nodes, but I think having a single node with this functionality would be quite handy.