hygiene, collapse the two cases GET_SER and GET_DAT

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
hygiene, don't pass on unused arguments to sub-routines

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, provide message type /raw? which utilises sendfile(3) to transmit the payload

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'feat/sendfile' into next

* feat/sendfile:
  minor, provide message type /raw? which utilises sendfile(3) to transmit the payload
  hygiene, don't pass on unused arguments to sub-routines
  hygiene, collapse the two cases GET_SER and GET_DAT