*           }
 *         });
 * }
 *
 * <p>The returned cache implements all optional operations of the {@link LoadingCache} and {@link
 * Cache} interfaces. The {@code asMap} view (and its collection views) have <i>weakly consistent
 * iterators</i>. This means that they are safe for concurrent use, but if other threads modify the
 * cache after the iterator is created, it is undefined which of these changes, if any, are

 * not consistent with equals, some of the standard implementations may violate the {@code Map}
 * contract.
 *
 * <p>The {@code standard} methods and the collection views they return are not guaranteed to be
 * thread-safe, even when all of the methods that they depend on are thread-safe.
 *
 * @author Louis Wasserman
 * @since 12.0
 */
@GwtIncompatible

import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.lang.reflect.WildcardType;
import java.security.AccessControlException;
import java.util.Arrays;
import java.util.Collection;
import java.util.Map.Entry;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicReference;
import org.jspecify.annotations.Nullable;

/**
 * Utilities for working with {@link Type}.
 *

import com.google.common.util.concurrent.Service.State;
import com.google.common.util.concurrent.ServiceManager.Listener;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.lang.reflect.InvocationTargetException;
import java.time.Duration;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.Delayed;
import java.util.concurrent.ExecutionException;

Translation of parameters and the return value follows the type
translation above except that arrays passed as parameters translate
explicitly in Go to pointers to arrays, as they do (implicitly) in C.

Garbage collection is the big problem.  It is fine for the Go world to
have pointers into the C world and to free those pointers when they
are no longer needed.  To help, the Go code can define Go objects

)

// tierConfigPath refers to remote tier config object name
var tierConfigPath = path.Join(minioConfigPrefix, tierConfigFile)

const tierCfgRefreshAtHdr = "X-MinIO-TierCfg-RefreshedAt"

// TierConfigMgr holds the collection of remote tiers configured in this deployment.
type TierConfigMgr struct {
	sync.RWMutex `msg:"-"`
	drivercache  map[string]WarmBackend `msg:"-"`

	Tiers           map[string]madmin.TierConfig `json:"tiers"`

  @Override
  public Set<K> keySet() {
    Set<K> ks = keySet;
    return (ks != null) ? ks : (keySet = new KeySet());
  }

  @LazyInit transient @Nullable Collection<V> values;

  @Override
  public Collection<V> values() {
    Collection<V> vs = values;
    return (vs != null) ? vs : (values = new Values());
  }

  @LazyInit transient @Nullable Set<Entry<K, V>> entrySet;

  @Override

import com.google.common.testing.NullPointerTester;
import com.google.common.testing.SerializableTester;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Map.Entry;
import java.util.Spliterator;
import java.util.function.BiPredicate;
import java.util.stream.Collector;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

 *   <li>To distinguish between "unknown" (for example, not present in a map) and "known to have no
 *       value" (present in the map, with value {@code Optional.absent()})
 *   <li>To wrap nullable references for storage in a collection that does not support {@code null}
 *       (though there are <a
 *       href="https://github.com/google/guava/wiki/LivingWithNullHostileCollections">several other
 *       approaches to this</a> that should be considered first)