Implement sequencer "shadow" feature

[rianhughes]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 49.65181% with 723 lines in your changes missing coverage. Please review.

Project coverage is 74.54%. Comparing base (107876a) to head (4fc301f).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
builder/builder.go	59.86%	133 Missing and 48 partials ⚠️
core/receipt.go	1.73%	113 Missing ⚠️
blockchain/blockchain.go	44.18%	55 Missing and 41 partials ⚠️
core/printers.go	0.00%	76 Missing ⚠️
core/state_update.go	40.17%	61 Missing and 9 partials ⚠️
genesis/genesis.go	61.53%	22 Missing and 18 partials ⚠️
mempool/mempool.go	70.94%	19 Missing and 15 partials ⚠️
node/node.go	48.27%	24 Missing and 6 partials ⚠️
adapters/vm2core/vm2core.go	61.97%	26 Missing and 1 partial ⚠️
node/genesis.go	0.00%	20 Missing ⚠️
... and 8 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2015      +/-   ##
==========================================
- Coverage   78.44%   74.54%   -3.90%     
==========================================
  Files         100      107       +7     
  Lines        9228    10553    +1325     
==========================================
+ Hits         7239     7867     +628     
- Misses       1350     1907     +557     
- Partials      639      779     +140     

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[rianhughes]

Squashing this PR into this #2173