message: Harden the mempool against a flood of new txs by discarding them earlier in validation
diff: @@ -223,8 +223,16 @@ where
  .enumerate()
  .filter_map(|(idx, t)| {
  if let Ok(sequence_number) = seq_numbers[idx] {
  - if t.sequence_number() >= sequence_number {
  + if t.sequence_number() == sequence_number {
  return Some((t, sequence_number));
  + } else if t.sequence_number() > sequence_number{
  + statuses.push((
  + t,
  + (
  + MempoolStatus::new(MempoolStatusCode::VmError),
  + Some(DiscardedVMStatus::SEQUENCE_NUMBER_TOO_NEW),
  + ),
  + ));
  }else {
  statuses.push((
  t,
  