I just had crazy idea that could improve the EmuNetDevice performance a bit.  Not sure if it us feasible, but wanted to note the idea somewhere before I forget.

Currently, to transmit a packet, EmuNetDevice does packet->CopyData, to copy data to another buffer, and then calls sendto().  Would it possible to implement a Copy-less serialization mechanism that used struct iovec and writev() instead?  We would need a new Packet method that returned an array of iovec, which points to its own internal data buffers, instead of copying the data elsewhere.  As a result, less data would need to be copied, for the transmission case.