I get a lot of spurious messages like this in the log:
```
2019-08-31T18:07:53Z Synchronizing blockheaders, height: 592633 (~100.00%)
2019-08-31T18:09:40Z Synchronizing blockheaders, height: 592634 (~100.00%)
2019-08-31T18:09:40Z Synchronizing blockheaders, height: 592634 (~100.00%)
2019-08-31T18:09:40Z Synchronizing blockheaders, height: 592634 (~100.00%)
2019-08-31T18:09:40Z Synchronizing blockheaders, height: 592634 (~100.00%)
2019-08-31T18:09:40Z Synchronizing blockheaders, height: 592634 (~100.00%)
2019-08-31T18:10:28Z Synchronizing blockheaders, height: 592635 (~100.00%)
2019-08-31T18:10:28Z Synchronizing blockheaders, height: 592635 (~100.00%)
2019-08-31T18:10:28Z Synchronizing blockheaders, height: 592635 (~100.00%)
2019-08-31T18:10:28Z Synchronizing blockheaders, height: 592635 (~100.00%)
2019-08-31T18:10:28Z Synchronizing blockheaders, height: 592635 (~100.00%)
2019-08-31T18:11:01Z Synchronizing blockheaders, height: 592636 (~100.00%)
2019-08-31T18:11:01Z Synchronizing blockheaders, height: 592636 (~100.00%)
2019-08-31T18:11:01Z Synchronizing blockheaders, height: 592636 (~100.00%)
2019-08-31T18:11:01Z Synchronizing blockheaders, height: 592636 (~100.00%)
2019-08-31T18:11:01Z Synchronizing blockheaders, height: 592636 (~100.00%)
```
also
```
2019-08-31T18:19:47Z New outbound peer connected: version: 70015, blocks=592636, peer=0
2019-08-31T18:19:47Z Synchronizing blockheaders, height: 592636 (~100.00%)
2019-08-31T18:19:47Z New outbound peer connected: version: 70015, blocks=592636, peer=1
2019-08-31T18:19:48Z Synchronizing blockheaders, height: 592636 (~100.00%)
2019-08-31T18:19:48Z New outbound peer connected: version: 70015, blocks=592636, peer=2
2019-08-31T18:19:49Z Synchronizing blockheaders, height: 592636 (~100.00%)
```
This log message was introduced in #15615 by @jonasschnelli..
From what I understand, it's supposed to only be shown once per 2000 blocks, not multiple times for the same block.


};
/**
 * Used to track blocks whose transactions were applied to the UTXO state as a
 * part of a single ActivateBestChainStep call.
 *
 * This class also tracks transactions that are removed from the mempool as
 * conflicts (per block) and can be used to pass all those transactions
 * through SyncTransaction.
 *
 * This class assumes (and asserts) that the conflicted transactions for a given
 * block are added via mempool callbacks prior to the BlockConnected() associated
 * with those transactions. If any transactions are marked conflicted, it is
 * assumed that an associated block will always be added.
 *
 * This class is single-use, once you call GetBlocksConnected() you have to throw
 * it away and make a new one.
 */
class ConnectTrace {