def snapshot
      { state: @state.root_hash,
        gas: gas_used,
        txs: @transactions,
        txcount: @transaction_count,
        refunds: refunds,
        suicides: suicides,
        suicides_size: suicides.size,
        logs: logs,
        logs_size: logs.size,
        journal: @journal, # pointer to reference, so is not static
        journal_size: @journal.size,
        ether_delta: ether_delta
      }
    end
def snapshot
      { state: @state.root_hash,
        gas: gas_used,
        txs: @transactions,
        txcount: @transaction_count,
        refunds: refunds,
        suicides: suicides,
        suicides_size: suicides.size,
        logs: logs,
        logs_size: logs.size,
        journal: @journal, # pointer to reference, so is not static
        journal_size: @journal.size,
        ether_delta: ether_delta
      }
    end
Make a snapshot of the current state to enable later reverting.