CreateConsensusEngine creates a consensus engine for the given chain config.

Synchronise the entire blockchain history from full blocks.

Download the chain and the state via compact snapshots.

Defaults contains default settings for use on the Ethereum main net.

FullNodeGPO contains default gasprice oracle settings for full node.

Config contains configuration options for ETH and LES protocols.

SyncMode represents the synchronisation mode of the downloader.