End processing of current HTTP request.
Note: All bytes of the current request should have been already
consumed. This method only resets all the pointers so that we are ready
to parse the next HTTP request.
Read the request line. This function is meant to be used during the
HTTP request header parsing. Do NOT attempt to read the request body
using it.
throws: IOException - If an exception occurs during the underlying socketread operations, or if the given buffer is not big enough to accomodatethe whole line.