Makes it possible to avoid copying or allocating in cases where DeliverNetworkPacket (rx)
needs to turn around and call WritePacket (tx) with its VectorisedView.
Also removes the restriction on having VectorisedViews with multiple views in the write path.
PiperOrigin-RevId: 211728717
Change-Id: Ie03a65ecb4e28bd15ebdb9c69f05eced18fdfcff
Establishes a way of communicating interface flags between netstack and
epsocket. More flags can be added over time.
PiperOrigin-RevId: 197616669
Change-Id: I230448c5fb5b7d2e8d69b41a451eb4e1096a0e30