* feat(query): fully async implementation of Kademlia lookup. peers returned from the lookup are not guaranteed to be alive (i.e. we're only guaranteed to have dialed the closest beta peers to the target), but given stable and correct routing tables the expectation that most of the peers returned are alive is high.
* feat(query): add wrapper lookup followup function to followup after the lookup is completed and ensure that the closest k returned peers from a lookup have been queried even for beta < k
* refactor(query) modified the structure returned from lookups to be a useful subset of the full query state instead of the entire query state
* feat(options): beta parameter exposed as the Resiliency parameter
* feat(routing): do not mark the routing table as updated after a FindPeer query
* feat(routing): FindPeer can return addresses even if not Connected as long as it was either recently connected (CanConnect) or was discovered during the lookup
* feat(bootstrap): bootstrap logic now uses GetClosestPeers instead of FindPeer
* refactor(dht): stopFn no longer takes any state
* fix(test): changed GetClosestPeers test to only assume beta instead of k peers since that is now more appropriate given the query logic changes and that the routing tables in that test are bad, i.e. a ring network with arbitrary peerIDs
Co-authored-by: Petar Maymounkov <petarm@gmail.com>
Co-authored-by: Aarsh Shah <aarshkshah1992@gmail.com>
1. Continue to best-effort provide, but still return an error when we fail to
send provider records to the _best_ peers.
2. Continue returning the best peer's we've found in GetClosestPeers, but also
return an error to indicate that we didn't find the closest ones.
And fix the hang test.
When the routing table is empty, `Run` would fail but _not_ close the
process (leaking some query goroutines). This patch fixes this in multiple
places by:
1. Not starting queries with no peers.
2. Failing queries with no peers earlier.
