If flowbit is set, unset it. If it is unset, set it. Toggle every bit specified or
toggle all the bits in group (Group must be present). This keyword always returns true.
flowbits: toggle, bit1&bit2
If bit1 is 0 and bit2 is 1 before, after this rule, bit1 is 1 and bit2 is 0.
Toggle all the bits in group doc as described above.