* Stop negotiating pivot if peer repeatedly replies w/usesless answers
why:
There is some fringe condition where a peer replies with legit but
useless empty headers repetely. This goes on until somebody stops.
We stop now.
* Rename `missingNodes` => `sickSubTries`
why:
These (probably missing) nodes represent in reality fully or partially
missing sub-tries. The top nodes may even exist, e.g. as a shallow
sub-trie.
also:
Keep track of account healing on/of by bool variable `accountsHealing`
controlled in `pivot_helper.execSnapSyncAction()`
* Add `nimbus` option argument `snapCtx` for starting snap recovery (if any)
also:
+ Trigger the recovery (or similar) process from inside the global peer
worker initialisation `worker.setup()` and not by the `snap.start()`
function.
+ Have `runPool()` returned a `bool` code to indicate early stop to
scheduler.
* Can import partial snap sync checkpoint at start
details:
+ Modified what is stored with the checkpoint in `snapdb_pivot.nim`
+ Will be loaded within `runDaemon()` if activated
* Forgot to import total coverage range
why:
Only the top (or latest) pivot needs coverage but the total coverage
is the list of all ranges for all pivots -- simply forgotten.