Wait for a slot event like smart card insertion or removal
WaitForSlotEvent waits for a slot event, such as token insertion or token removal, to
occur. flags determines whether or not the WaitForSlotEvent call blocks (i.e., waits
for a slot event to occur);
At present, the only flag defined for use in the flags argument is CKF_DONT_BLOCK:
Internally, each Cryptoki application has a flag for each slot which is used to track
whether or not any unrecognized events involving that slot have occurred.