- Fix slowness when operating over fast connections, where the timeout(9)
granularity is on the same order of magnitude as the round trip time.
timeout(9) can happen up to 1 tick early, which was causing receive
ack timeouts to happen too early, causing bogus "lost" packets.
- Increase the local time counter to 64 bits to avoid roll-over.
- Keep statistics on memory allocation failures.
- Add a new option to always include the ack when sending data packets.
Might be useful in high packet loss situations. Might not.