}
    }
    return added;
  }

  /**
   * Returns a synchronized (thread-safe) queue backed by the specified queue. In order to guarantee
   * serial access, it is critical that <b>all</b> access to the backing queue is accomplished
   * through the returned queue.
   *
   * <p>It is imperative that the user manually synchronize on the returned queue when accessing the
   * queue's iterator:
   *
   * <pre>{@code

	if err != nil {
		if xnet.IsNetworkOrHostDown(err, expectTimeouts) {
			if !c.NoMetrics {
				atomic.AddUint64(&globalStats.errs, 1)
			}
			if c.MarkOffline(err) {
				logger.LogOnceIf(ctx, logSubsys, fmt.Errorf("Marking %s offline temporarily; caused by %w", c.url.Host, err), c.url.Host)
			}
		}
		return nil, &NetworkError{err}
	}

	// If trace is enabled, dump http request and response,

   * #toMap(Iterable, Function)}.
   *
   * <p>Specifically, for each {@code k} in the backing set, the returned map has an entry mapping
   * {@code k} to {@code function.apply(k)}. The {@code keySet}, {@code values}, and {@code
   * entrySet} views of the returned map iterate in the same order as the backing set.
   *
   * <p>Modifications to the backing set are read through to the returned map. The returned map

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A set which forwards all its method calls to another set. Subclasses should override one or more
 * methods to modify the behavior of the backing set as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>Warning:</b> The methods of {@code ForwardingSet} forward <b>indiscriminately</b> to the

     * than two.)
     *
     * Read operations can thus proceed without locking, but rely on selected uses of volatiles to
     * ensure that completed write operations performed by other threads are noticed. For most
     * purposes, the "count" field, tracking the number of elements, serves as that volatile

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A sorted map which forwards all its method calls to another sorted map. Subclasses should
 * override one or more methods to modify the behavior of the backing sorted map as desired per the
 * <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>Warning:</b> The methods of {@code ForwardingSortedMap} forward <i>indiscriminately</i> to

 * [Fresco](https://github.com/facebook/fresco): An Android library for managing images and the memory they use.
 * [Glide](https://github.com/bumptech/glide): An image loading and caching library for Android focused on smooth scrolling.
 * [GoogleAppEngineOkHttp](https://github.com/apkelly/GoogleAppEngineOkHttp): An OkHttp Call that works on Google App Engine.

import javax.security.auth.RefreshFailedException;

/** Microbenchmark for {@link Futures#getChecked}. */
public class FuturesGetCheckedBenchmark {
  private enum Validator {
    NON_CACHING_WITH_CONSTRUCTOR_CHECK(nonCachingWithConstructorCheckValidator()),
    NON_CACHING_WITHOUT_CONSTRUCTOR_CHECK(nonCachingWithoutConstructorCheckValidator()),
    WEAK_SET(weakSetValidator()),
    ;

    final GetCheckedTypeValidator validator;

 * {@link #computeNext} method, and invoke the {@link #endOfData} method when appropriate.
 *
 * <p>Another example is an iterator that skips over null elements in a backing iterator. This could
 * be implemented as:
 *
 * <pre>{@code
 * public static Iterator<String> skipNulls(final Iterator<String> in) {
 *   return new AbstractIterator<String>() {
 *     protected String computeNext() {

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A deque which forwards all its method calls to another deque. Subclasses should override one or
 * more methods to modify the behavior of the backing deque as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>Warning:</b> The methods of {@code ForwardingDeque} forward <b>indiscriminately</b> to the