locking, in the computing device, {TAIL ~ a first feature instance} identified in {HEAD ~ the request} 
locking , in the computing device , { TAIL ~ a first feature instance } identified in { HEAD ~ the request }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD