UnityNextULP.cs

    // Given a float f, return next possible representation.
    // This method will have issues around +/-maxfloat, +/-infinity, NaN.
    //
    public static float NextULP(float f, int ulp=1)
    {
        int bits = System.BitConverter.SingleToInt32Bits(f);
        return System.BitConverter.Int32BitsToSingle(bits + ulp);
    }

ULP - Unit of Least Precision.

Floating point numbers with limited bits cannot express all possible values. The delta between possible values varies as the distance from zero increases. In IEEE754, neighboring float values are consecutive binary values because the mantissa is stored in the lowest significant bits and the exponent is immediately the next more significant bits (so overflow of the mantissa immediately affects the exponent correctly).

Shout out to https://www.h-schmidt.net/FloatConverter/IEEE754.html to visualize things like this.