accept headers in mesh and textures.  For texture metrics
reporting, use the AP_INVENTORY policy class which is
non-pipelined and pointing (usually) in the right direction.
Use a do-while(false) structure to manage common exit path
code in onCompleted() methods.  Identical to a 'goto' but
might amuse the pedantic.  Tuning on background fetch to
have it cycle faster.  This is experimental.  I suspect
with HTTP balancing in llcorehttp, we can do away with the
timers here.