class Eth::Tx

def intrinsic_gas_used
  num_zero_bytes = data_bin.count(BYTE_ZERO)
  num_non_zero_bytes = data_bin.size - num_zero_bytes
  Gas::GTXCOST +
    Gas::GTXDATAZERO * num_zero_bytes +
    Gas::GTXDATANONZERO * num_non_zero_bytes
end