This command allows you to set the bit at index bit in oldValue to either 1 or 0.
If onOff is passed as 0 then the bit is set to 0. If onOff is non-zero then the bit is set to 1.
The bit indexes are numbered 0 through to 31, where 0 is the least significant bit, and 31 is the most significant bit.
It is possible to test if an individual bit is already set using the Bit Test command.