Remove octet values from the given array that ZMODEM always ignores.
This will mutate the given array.

@param {number[]} octets - The octet values to transform.
Each array member should be an 8-bit unsigned integer (0-255).
This object is mutated in the function.

@returns {number[]} The passed-in array. This is the same object that is
passed in.
function strip_ignored_bytes(octets) {
        for (var o=octets.length-1; o>=0; o--) {
            switch (octets[o]) {
                case XON:
                case XON_HIGH:
                case XOFF:
                case XOFF_HIGH:
                    octets.splice(o, 1);
                    continue;
            }
        }

        return octets;
    }