* batch attestations
* Fixes (but now need to investigate the chronos 0 .. 4095 crash similar to https://github.com/status-im/nimbus-eth2/issues/1518
* Try to remove the processing loop to no avail :/
* batch aggregates
* use resultsBuffer size for triggering deadline schedule
* pass attestation pool tests
* Introduce async gossip validators. May fix the 4096 bug (reentrancy issue?) (similar to sync unknown blocks #1518)
* Put logging at debug level, add speed info
* remove unnecessary batch info when it is known to be one
* downgrade some logs to trace level
* better comments [skip ci]
* Address most review comments
* only use ref for async proc
* fix exceptions in eth2_network
* update async exceptions in gossip_validation
* eth2_network 2nd pass
* change to sleepAsync
* Update beacon_chain/gossip_processing/batch_validation.nim
Co-authored-by: Jacek Sieka <jacek@status.im>
Co-authored-by: Jacek Sieka <jacek@status.im>
* set upper bound on EpochRef cache
* max 32 EpochRef instances
* less memory waste in BlockRef by removing EpochRef seq that is mostly
unused (~20mb)
* less memory waste in dag block lookup by not keeping an extra copy of
digest (~70mb)
* fix `==` and `$` for Eth2Digest
* remove `ChainDAG.tmpState` (~50mb?)
all in all, this branch cuts mainnet memory usage by ~160-180mb and puts
limits on EpochRef cache usage - where normally it hovered around 950mb
before, it's now sitting at 600-700mb on my machine.
* docs
Dustin Brody
Mamy Ratsimbazafy
Jacek Sieka