a) submitting the received request in an unmodified form to the application on behalf of the client device and receiving {HEAD ~ output} from {TAIL ~ the application} responsive to the submitted request 
from
a ) submitting the received request in an unmodified form to the application on behalf of the client device and receiving { HEAD ~ output } from { TAIL ~ the application } responsive to the submitted request
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH