transaction example

This is a very simple example showing how to use TransactionManager. This example shows how to begin a transaction, commit a transaction, and rollback a transaction while showing exception handling. We commit two keys and rollback adding a third key and destroying an existing key while showing how to handle exceptions.

Prerequisites

Install Apache Geode
Build and install Apache Geode Native
Apache Geode Native examples, built and installed
Set GEODE_HOME to the install directory of Apache Geode

Running

From a command shell, set the current directory to the transaction directory in your example workspace.
```
$ cd workspace/examples/cpp/transaction
```
Run the startserver script to start the Geode cluster with authentication and create a region.
For Windows cmd:
```
$ powershell.exe -File startserver.ps1
```
For Windows Powershell:
```
$ startserver.ps1
```
For Bash:
```
$ ./startserver.sh
```
Execute cpp-transaction. The output logs the cache and region creation, and the results of up to five attempts to commit the transaction. Example execution ends when the transaction is successfully committed, or when the maximum number of attempts is reached without a successful commit.

For example, this run ends in a successful commit:

```bash
$ ./cpp-transaction
   Created cache
   Created region 'exampleRegion'
   Rolled back transaction - retrying(4)
   Rolled back transaction - retrying(3)
   Rolled back transaction - retrying(2)
   Committed transaction - exiting
```

In contrast, this run ends without a successful commit, after five unsuccessful attempts:

```bash
$ ./cpp-transaction
   Created cache
   Created region 'exampleRegion'
   Rolled back transaction - retrying(4)
   Rolled back transaction - retrying(3)
   Rolled back transaction - retrying(2)
   Rolled back transaction - retrying(1)
   Rolled back transaction - retrying(0)       
```

Run the stopserver script to gracefully shutdown the Geode cluster.
For Windows cmd:
```
$ powershell.exe -File stopserver.ps1
```
For Windows Powershell:
```
 $ stopserver.ps1
```
For Bash:
```
$ ./stopserver.sh
```