* Send headers continuously without needing to run the BlockLocator protocol after ever ~maxBlueScoreDifference blocks
* Add logging.
* Make logs more descriptive.
* Remove the limit on the amount of hashes returned from antiPastHashesBetween.
* Guard against requests with a non-existing block hash.
* Move missing-block-hash guards to consensus.go.
* Ban a peer that doesn't send us all the requested headers during IBD.
* Extract blockHeap.ToSlice.
* Re-request headers in requestHeaders if we didn't receive the highHash.
* [NOD-1579] Remove selected tip hash messages.
* [NOD-1579] Start moving IBD stuff into blockrelay.
* [NOD-1579] Rename relaytransactions to transactionrelay.
* [NOD-1579] Move IBD files into blockrelay.
* [NOD-1579] Remove flow stuff from ibd.go.
* [NOD-1579] Bring back IsInIBD().
* [NOD-1579] Simplify block relay flow.
* [NOD-1579] Check orphan pool for missing parents to avoid unnecessary processing.
* [NOD-1579] Implement processOrphan.
* [NOD-1579] Implement addToOrphanSetAndRequestMissingParents.
* [NOD-1579] Fix TestIBD.
* [NOD-1579] Implement isBlockInOrphanResolutionRange.
* [NOD-1579] Implement limited block locators.
* [NOD-1579] Add some comments.
* [NOD-1579] Specifically check for StatusHeaderOnly in blockrelay.
* [NOD-1579] Simplify runIBDIfNotRunning.
* [NOD-1579] Don't run IBD if it is already running.
* [NOD-1579] Fix a comment.
* [NOD-1579] Rename mode to syncInfo.
* [NOD-1579] Simplify validateAndInsertBlock.
* [NOD-1579] Fix bad SyncStateSynced condition.
* [NOD-1579] Implement validateAgainstSyncStateAndResolveInsertMode.
* [NOD-1579] Use insertModeHeader.
* [NOD-1579] Add logs to TrySetIBDRunning and UnsetIBDRunning.
* [NOD-1579] Implement and use dequeueIncomingMessageAndSkipInvs.
* [NOD-1579] Fix a log.
* [NOD-1579] Fix a bug in createBlockLocator.
* [NOD-1579] Rename a variable.
* [NOD-1579] Fix a slew of bugs in missingBlockBodyHashes and selectedChildIterator.
* [NOD-1579] Fix bad chunk size in syncMissingBlockBodies.
* [NOD-1579] Remove maxOrphanBlueScoreDiff.
* [NOD-1579] Fix merge errors.
* [NOD-1579] Remove a debug log.
* [NOD-1579] Add logs.
* [NOD-1579] Make various go quality tools happy.
* [NOD-1579] Fix a typo in a variable name.
* [NOD-1579] Fix full blocks over header-only blocks not failing the missing-parents validation.
* [NOD-1579] Add an error log about a condition that should never happen.
* [NOD-1579] Check all antiPast hashes instead of just the lowHash's anticone to filter for header-only blocks.
* [NOD-1579] Remove the nil stuff from GetBlockLocator.
* [NOD-1579] Remove superfluous condition in handleRelayInvsFlow.start().
* [NOD-1579] Return a boolean from requestBlock instead of comparing to nil.
* [NOD-1579] Fix a bad log.Debugf.
* [NOD-1579] Remove a redundant check.
* [NOD-1579] Change an info log to a warning log.
* [NOD-1579] Move OnNewBlock out of relayBlock.
* [NOD-1579] Remove redundant exists check from runIBDIfNotRunning.
* [NOD-1579] Fix bad call to OnNewBlock.
* [NOD-1579] Remove an impossible check.
* [NOD-1579] Added a log.
* [NOD-1579] Rename insertModeBlockWithoutUpdatingVirtual to insertModeBlockBody.
* [NOD-1579] Add a check for duplicate headers.
* [NOD-1579] Added a comment.
* [NOD-1579] Tighten a stop condition.
* [NOD-1579] Simplify a log.
* [NOD-1579] Clarify a log.
* [NOD-1579] Move a log.
