// authenticationManager orchestrates all authenticators to perform authentication.
type authenticationManager struct {
	Authenticators []Authenticator
	// authFailMsgs contains list of messages that authenticator wants to record - mainly used for logging.
	authFailMsgs []string
}

// Authenticate loops through all the configured Authenticators and returns if one of the authenticator succeeds.

        <configuration>
          <asfExtOptions>
            <charter>The mission of the Apache Maven project is to create and maintain software
            libraries that provide a widely-used project build tool, targeting mainly Java
            development. Apache Maven promotes the use of dependencies via a
            standardized coordinate system, binary plugins, and a standard build
            lifecycle.</charter>
          </asfExtOptions>

	var services []*model.Service
	// Holds clusters per service, keyed by hostname.
	serviceClusters := make(map[string]sets.String)
	// Holds service ports, keyed by hostname.Inner map port and its cluster name.
	// This is mainly used when service is updated and a port has been removed.
	servicePortClusters := make(map[string]map[int]string)
	// Holds subset clusters per service, keyed by hostname.
	subsetClusters := make(map[string]sets.String)

// These flags are mainly for tools that understand the module graph.
// Users should prefer 'go get path@version' or 'go get path@none',
// which make other go.mod adjustments as needed to satisfy
// constraints imposed by other modules.
//
// The -go=version flag sets the expected Go language version.
// This flag is mainly for tools that understand Go version dependencies.

		c.groupResource,
		identifier,
	)

	// note that c.waitUntilWatchCacheFreshAndForceAllEvents must be called without
	// the c.watchCache.RLock held otherwise we are at risk of a deadlock
	// mainly because c.watchCache.processEvent method won't be able to make progress
	//
	// moreover even though the c.waitUntilWatchCacheFreshAndForceAllEvents acquires a lock

	// queueingHintMap is keyed with profile name, valued with registered queueing hint functions.
	queueingHintMap QueueingHintMapPerProfile

	// closed indicates that the queue is closed.
	// It is mainly used to let Pop() exit its control loop while waiting for an item.
	closed bool

	nsLister listersv1.NamespaceLister

	metricsRecorder metrics.MetricAsyncRecorder

		// xl.meta has "inlined data" we prefer writing O_DIRECT and then doing
		// fdatasync() at the end instead of opening the file with O_DSYNC.
		//
		// This is an optimization mainly to ensure faster I/O.
		if len(b) > xioutil.DirectioAlignSize {
			r := bytes.NewReader(b)
			return s.writeAllDirect(ctx, filePath, r.Size(), r, flags, skipParent)
		}

This was designed this way mainly to allow using the same objects "yielded" by dependencies inside of background tasks, because the exit code would be executed after the background tasks were finished.

Returns the timestamp as a `float64` for seconds since the Unix epoch.

Common usages include:
* Logging
* Providing a random number seed
* Debugging graph execution
* Generating timing information, mainly through comparison of timestamps

Note: In graph mode, the timestamp is computed when the op is executed,
not when it is added to the graph.  In eager mode, the timestamp is computed
when the op is eagerly executed.