* Bump nim-eth to get UseDiscv51 flag
* Switch medalla to discovery v5.1, other targets to v5.0
* Bump nim-eth for better discv5.1 logging
* Bump eth2-testnets for updated medalla bootnodes
* addPeer() and addPeerNoWait() now returns PeerStatus, not bool.
Minor refactoring of PeerPool.
Fix tests.
* Refactor PeerPool.
Add lenSpace.
Add tests for lenSpace.
PeerPool.add procedures now return different error codes.
Fix SyncManager break/continue problem.
Fix connectWorker break/continue problem.
Refactor connectWorker and discoveryLoop.
Fix incoming/outgoing blocking problem.
* Refactor discovery loop.
Add checkPeer.
* Fix logic and compilation bugs.
* Adjust position of debugging log.
* Fix issue with maximum peers in PeerPool.
Optimize node record decoding.
* fix discoveryLoop.
* Remove aliases and fix tests using aliases.
* Refactor peer_pool.
Fix eth2_network peer counters.
Fix PeerPool do not allow to add more peers when empty space available.
* Remove unused imports.
* Add test for a bug.
* Fix eth2_network disconnect should deletePeer not release.
More PeerPool refactoring.
* remove some superfluous gcsafes
* remove getTailState (unused)
* don't store old epochrefs in blocks
* document attestation pool a bit
* remove `pcs =` cruft from log
per spec, we must half-close request stream - not doing so may lead to
failure of the other end to start processing our request leading to
timeouts.
In particular, this fixes many sync problems that have been seen on
medalla.
* remove safeClose - close no longer raises
* use per-chunk timeouts in request processing
When blocks and attestations arrive, they are SSZ-decoded twice: once
for validation and once for processing. This branch enqueues the decoded
block directly for processing, avoiding the second, slow
deserialization.
* move processing of blocks and attestations to queue
* ...and out from beacon_node
* split attestation processing into attestations and aggregates
* also updates metrics
* clean up logging to better follow the lifetime of gossip: arrival,
validation and processing
* drop attestations and aggregates if there are too many
* try to prioritise blocks and aggregates before single-validator
attestations
removed in 0.12.2 - the flow, in particular when the other peer doesn't
support snappy, is hard to follow because of the trial-and-error
approach - removing it simplifies things and removes some of the
hard-to-read parts of the thunking etc
this resolves some peer counting issues that were happening because the
lifetime future in PeerInfo was unreliable (multiple PeerInfo instances
existed per peer)
In addition, this solves another race condition: when connecting to a
peer and later dialling that protocol, it is not certain that the same
connection will be used if there's a concurrent incoming peer connection
ongoing - better not make too many assumptions about who sent statuses
when.
