code: func (b *backendInstance) PendingNonceAt(ctx context.Context, account common.Address) (uint64, error) {
  	ctx, cancel := b.addTimeout(ctx)
  	defer cancel()
  	return b.conn.ethClient().PendingNonceAt(ctx, account)
  }
docs: // PendingNonceAt returns the account nonce of the given account in the pending state.
  // This is the nonce that should be used for the next transaction.