public async Task <Unit> Handle(TransferCommand request, CancellationToken cancellationToken)
{
var transaction = await _transactionsTable.GetByIdAsync(request.TransactionId);
var writeOffAccount = await _accountsTable.GetAsync(transaction.WriteOffAccount, transaction.UserId);
ValidateWriteOffAccount(writeOffAccount, transaction);
var destinationAccount = await _accountsTable.GetByIdAsync(transaction.DestinationAccount);
ValidateDestinationAccount(destinationAccount, transaction);
writeOffAccount.Balance -= transaction.Amount;
writeOffAccount.LastModified = DateTime.UtcNow;
destinationAccount.Balance += transaction.Amount;
destinationAccount.LastModified = DateTime.UtcNow;
await _accountsTable.UpdateAsync(writeOffAccount);
await _accountsTable.UpdateAsync(destinationAccount);
return(Unit.Value);
}