OkHttpClient uses a connection pool. Its job is to maintain a reference to all open connections. When an HTTP request is started, OkHttp will attempt to reuse an existing connection from the pool. If there are no existing connections, a new one is created and put into the connection pool. For HTTP/2, the connection can be reused immediately. For HTTP/1, the request must be completed before it can be reused.

Since HTTP requests frequently happen in parallel, connection pooling must be thread-safe....

### Create an `Enum` class

Import `Enum` and create a sub-class that inherits from `str` and from `Enum`.

By inheriting from `str` the API docs will be able to know that the values must be of type `string` and will be able to render correctly.

Then create class attributes with fixed values, which will be the available valid values:

@Named
@Singleton
@Deprecated(since = "4.0.0")
public class DefaultSuperPomProvider implements SuperPomProvider {

    private final ModelProcessor modelProcessor;

    /**
     * The cached super POM, lazily created.
     */
    private static final Map<String, Model> SUPER_MODELS = new ConcurrentHashMap<>();

    @Inject
    public DefaultSuperPomProvider(ModelProcessor modelProcessor) {
        this.modelProcessor = modelProcessor;

uptions/ ## podDisruptionBudget: enabled: false maxUnavailable: 1 ## Specify the service account to use for the MinIO pods. If 'create' is set to 'false' ## and 'name' is left unspecified, the account 'default' will be used. serviceAccount: create: true ## The name of the service account to use. If 'create' is 'true', a service account with that name ## will be created. name: "minio-sa" metrics: serviceMonitor: enabled: false public: true additionalLabels: {} relabelConfigs: {} # namespace: monitoring...

uptions/ ## podDisruptionBudget: enabled: false maxUnavailable: 1 ## Specify the service account to use for the MinIO pods. If 'create' is set to 'false' ## and 'name' is left unspecified, the account 'default' will be used. serviceAccount: create: true ## The name of the service account to use. If 'create' is 'true', a service account with that name ## will be created. name: "minio-sa" metrics: serviceMonitor: enabled: false public: true additionalLabels: {} relabelConfigs: {} # namespace: monitoring...

uptions/ ## podDisruptionBudget: enabled: false maxUnavailable: 1 ## Specify the service account to use for the MinIO pods. If 'create' is set to 'false' ## and 'name' is left unspecified, the account 'default' will be used. serviceAccount: create: true ## The name of the service account to use. If 'create' is 'true', a service account with that name ## will be created. name: "minio-sa" metrics: serviceMonitor: enabled: false public: true additionalLabels: {} relabelConfigs: {} # namespace: monitoring...

uptions/ ## podDisruptionBudget: enabled: false maxUnavailable: 1 ## Specify the service account to use for the Minio pods. If 'create' is set to 'false' ## and 'name' is left unspecified, the account 'default' will be used. serviceAccount: create: true ## The name of the service account to use. If 'create' is 'true', a service account with that name ## will be created. name: "minio-sa" metrics: serviceMonitor: enabled: false additionalLabels: {} public: true # namespace: monitoring # interval: 30s...

## Install dependencies

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and install `jinja2`:

<div class="termy">

```console
$ pip install jinja2

---> 100%
```

</div>

## Using `Jinja2Templates`

* Import `Jinja2Templates`.
* Create a `templates` object that you can reuse later.

          if (isShutdown) return

          // If the stream ID is less than the last created ID, assume it's already closed.
          if (streamId <= lastGoodStreamId) return

          // If the stream ID is in the client's namespace, assume it's already closed.
          if (streamId % 2 == nextStreamId % 2) return

          // Create a stream.
          val headers = headerBlock.toHeaders()

uptions/ ## podDisruptionBudget: enabled: false maxUnavailable: 1 ## Specify the service account to use for the MinIO pods. If 'create' is set to 'false' ## and 'name' is left unspecified, the account 'default' will be used. serviceAccount: create: true ## The name of the service account to use. If 'create' is 'true', a service account with that name ## will be created. name: "minio-sa" metrics: serviceMonitor: enabled: false # scrape each node/pod individually for additional metrics includeNode:...