Function ethcore::snapshot::verify_old_block

pub fn verify_old_block(
    rng: &mut OsRng, 
    header: &Header, 
    engine: &EthEngine, 
    chain: &BlockChain, 
    always: bool
) -> Result<(), Error>

Verify an old block with the given header, engine, blockchain, body. If always is set, it will perform the fullest verification possible. If not, it will take a random sample to determine whether it will do heavy or light verification.