function hardSigmoid(x) {
	  return tidy(function () {
	    var y = add$1(.5, mul(.2, x));
	    return clipByValue(y, 0, 1);
	  });
	}
Element-wise, segment-wise linear approximation of sigmoid.

Returns `0.` if `x < -2.5`, `1.` if `x > 2.5`.
In `-2.5 <= x <= 2.5`, returns `0.2 * x + 0.5`.

@param x Input tensor.
@returns Output tensor.