* interface

* generalize interface

* linters

* fix deadlock

* fix linters

* close goroutine

* fix

* debug

* id+ttl

* refactor downloader tests

* tests

* lru

* handle genesis, extract fake consensuses

* fix fake consensus

* test uncles, verify

* after a new master

* fmt

* fix close

* debug

* debug

* fix chain length

* remove test field

* use single account

* fix data race on closing channel

* remove postponed blocks queue

* miner test

* VerifyHeaderRequests

* fmt

* fmt

* fix data race

* handle validating errors

* simplify matchParents

* remove copy-paste

* move sort to constructor

* clean up

* debug for 10 parents

* debug

* debug

* batch responses

* batch requests

* works for many ancestors

* remove debug

* always Close an engine

* linters

* ancestors deduplication

* fix test

* reduce interface

* api

* clique

* green clique sync

* stable

* perpermance per second

* full sync

* linters

* gitignore

* deps

* fix panic after master merge

* init consensus

* clique tests

* fix tests

* fix tests

* clean up

* reuse snap

* store vefified snapshots

* optimize snapshots

* safe close

* cleanup loop

* after downloader

* downloader and consensus tests

* update tests

* hack.go

* clique flags

* fix cliuqe config

* review

* gitignore

* remove additional bucket

* blk/sec instead of blk/microsecond

* rename

* deps

* optimize

* debug

* test

* tests without extracted validation process

* same base performance as on master

* benchmark

* simplify ethash verification

* ethash

* ethash

* linters

* ethash

* master stats

* cleanup

* gomod

* linters

* tests

* better locks

* Fix

* Remove logging for verifyHeaders

* Verification speed in the logs

* Fix compile error

Co-authored-by: Alexey Sharp <alexeysharp@Alexeys-iMac.local>