Our CORK logic was wrong, and it's better to use Nagle anyway:
we disable Nagle just before sending timing-critical messages.
Time for 100 (failed) payments:
Before:
148.8573575
After:
10.7356977
Note this revealed a timing problem in test_reject_invalid_payload: we would
miss the cause of the sendonion failure, and waitsendpay would be called
*after* it had failed, so simply returns "Payment failure reason unknown".
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Fixed: Protocol: Removed 200ms latency from sending commit/revoke messages.