Applies the hardswish function, element-wise, as described in the paper: Searching for MobileNetV3.
nnf_hardswish(input, inplace = FALSE)
(N,*) tensor, where * means, any number of additional dimensions
can optionally do the operation in-place. Default: FALSE
$$ \mbox{Hardswish}(x) = \left\{ \begin{array}{ll} 0 & \mbox{if } x \le -3, \\ x & \mbox{if } x \ge +3, \\ x \cdot (x + 3)/6 & \mbox{otherwise} \end{array} \right. $$