generating, in the computing device, {TAIL ~ an identifier} that is associated with the lock on {HEAD ~ the first feature instance} and returning the identifier to the client 
generating , in the computing device , { TAIL ~ an identifier } that is associated with the lock on { HEAD ~ the first feature instance } and returning the identifier to the client
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH