Module snap 

Runs a snap/2 bootstrap as the engine’s backfill.

One task alternates header sync and snap state writes while the engine skips forkchoice, so no other writer touches the database. Each pass:

1. Syncs headers to the target; nothing below the pivot executes.
2. Selects a pivot under the head, or resumes the recorded attempt while its pivot is canonical.
3. Downloads state against the pivot’s root, carried to newer pivots by block access lists.
4. Hands the state to SnapHandoff, which rebuilds the trie and publishes it at the pivot, or abandons the attempt on a root mismatch so the next pass starts a new one.

A forkchoice update ends the current step at its next boundary, so headers catch up first. The staged pipeline then runs the stages above the pivot.

Structs

SnapBackfillSync

Backfills canonical headers, then snap/2 state at a recent pivot.

SnapHandoff

Hands one attempt’s downloaded state over to the staged pipeline.

Enums

EthereumBackfill

Builds the Ethereum node’s backfill: the staged pipeline, or snap sync with --snap.v2.

EthereumBackfillSync

The Ethereum node’s backfill: the staged pipeline, or snap sync.

HandoffOutcome

What a handoff did with the downloaded state.

RebuildOutcome

How a trie rebuild ended.