- we need to deal with a shared context for plugins, like the guarded mojos
- we need to deal with plugins as core application logic which can also interact with plugins

* Along with this comes the testing strategies that make this work
* The repository model where plugins can be stored and cataloged
* Bridging this into an OSGi system: if this could be done then we can basically take over p2

TODO

      this License, each Contributor hereby grants to You a perpetual,
      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      (except as stated in this section) patent license to make, have made,
      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their

# Settings and Environment Variables { #settings-and-environment-variables }

In many cases your application could need some external settings or configurations, for example secret keys, database credentials, credentials for email services, etc.

Most of these settings are variable (can change), like database URLs. And many could be sensitive, like secrets.

For this reason it's common to provide them in environment variables that are read by the application.

/// tip

}

// GetLastDayTierStats fetches per-tier stats of the last 24hrs from all peers
func (sys *NotificationSys) GetLastDayTierStats(ctx context.Context) DailyAllTierStats {
	errs := make([]error, len(sys.allPeerClients))
	lastDayStats := make([]DailyAllTierStats, len(sys.allPeerClients))
	var wg sync.WaitGroup
	for index := range sys.peerClients {
		if sys.peerClients[index] == nil {
			continue
		}
		wg.Add(1)

 *
 * <p>Listeners are registered once via {@link #addListener} and then may be invoked by {@linkplain
 * #enqueue enqueueing} and then {@linkplain #dispatch dispatching} events.
 *
 * <p>The API of this class is designed to make it easy to achieve the following properties
 *
 * <ul>
 *   <li>Multiple events for the same listener are never dispatched concurrently.
 *   <li>Events for the different listeners are dispatched concurrently.

		}
	}
}

// Test for reduceErrs, reduceErr reduces collection
// of errors into a single maximal error with in the list.
func TestReduceErrs(t *testing.T) {
	canceledErrs := make([]error, 0, 5)
	for i := range 5 {
		canceledErrs = append(canceledErrs, fmt.Errorf("error %d: %w", i, context.Canceled))
	}
	// List all of all test cases to validate various cases of reduce errors.
	testCases := []struct {

		// We may also synthesize additional directory entries.
		r.fileList = make([]fileListEntry, 0, len(r.File))
		// files and knownDirs map from a file/directory name
		// to an index into the r.fileList entry that we are
		// building. They are used to mark duplicate entries.
		files := make(map[string]int)
		knownDirs := make(map[string]int)

		// dirs[name] is true if name is known to be a directory,

In most setups this will keep the scanner slow enough to not impact overall system performance. Setting the `delay` key to a *lower* value will make the scanner faster and setting it to 0 will make the scanner run at full speed (not recommended in production). Setting it to a higher value will make the scanner slower, consuming less resources with the trade off of not collecting metrics for operations like healing and disk usage as fast.

```

	subStateless map[subHandlerID]*StatelessHandler
	subStreams   map[subHandlerID]*StreamHandler
}

func (h *handlers) init() {
	h.subSingle = make(map[subHandlerID]SingleHandlerFn)
	h.subStateless = make(map[subHandlerID]*StatelessHandler)
	h.subStreams = make(map[subHandlerID]*StreamHandler)
}

func (h *handlers) hasAny(id HandlerID) bool {
	if !id.valid() {
		return false
	}

      this License, each Contributor hereby grants to You a perpetual,
      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      (except as stated in this section) patent license to make, have made,
      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their