* 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.
* Piecemeal trie inspection
details:
Trie inspection will stop after maximum number of nodes visited.
The inspection can be resumed using the returned state from the
last session.
why:
This feature allows for task switch between `piecemeal` sessions.
* Extract pivot helper code from `worker.nim` => `pivot_helper.nim`
* Accounts import will now return dangling paths from `proof` nodes
why:
With proper bookkeeping, this can be used to start healing without
analysing the the probably full trie.
* Update `unprocessed` account range handling
why:
More generally, the API of a pairs of unprocessed intervals favours
the first set and not before that is exhausted the second set comes
into play.
This was unfortunately implemented which caused the ranges to be
unnecessarily fractioned. Now the number of range interval typically
remains in the lower single digit numbers.
* Save sync state after end of downloading some accounts
details:
restore/resume to be implemented later
Jordan Hrycaj