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