code: func (ec *Client) PendingNonceAt(ctx context.Context, account common.Address) (uint64, error) {
  	var result hexutil.Uint64
  	err := ec.c.CallContext(ctx, &result, "eth_getTransactionCount", account, "pending")
  	return uint64(result), err
  }
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.