else -> {
        toEvict = null
        toEvictIdleAtNs = -1L
      }
    }

    when {
      toEvict != null -> {
        // We've chosen a connection to evict. Confirm it's still okay to be evicted, then close it.
        toEvict.withLock {
          if (toEvict.calls.isNotEmpty()) return 0L // No longer idle.
          if (toEvict.idleAtNs != toEvictIdleAtNs) return 0L // No longer oldest.

Once the response has been received, the connection will be returned to the pool so it can be reused for a future request. Connections are evicted from the pool after a period of inactivity.

### [Fast Fallback](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-ok-http-client/-builder/fast-fallback/)

 *
 * <p>If {@link #maximumSize(long) maximumSize} or {@link #maximumWeight(long) maximumWeight} is
 * requested entries may be evicted on each cache modification.
 *
 * <p>If {@link #expireAfterWrite expireAfterWrite} or {@link #expireAfterAccess expireAfterAccess}
 * is requested entries may be evicted on each cache modification, on occasional cache accesses, or

 * application. The tuning parameters in this pool are subject to change in future OkHttp releases.
 * Currently this pool holds up to 5 idle connections which will be evicted after 5 minutes of
 * inactivity.
 */
class ConnectionPool internal constructor(
  internal val delegate: RealConnectionPool,
) {
  internal constructor(
    maxIdleConnections: Int = 5,

 *             for loading to complete (whether successful or not) and then increment {@code
 *             missCount}.
 *       </ul>
 *   <li>When an entry is evicted from the cache, {@code evictionCount} is incremented.
 *   <li>No stats are modified when a cache entry is invalidated or manually removed.

 *             for loading to complete (whether successful or not) and then increment {@code
 *             missCount}.
 *       </ul>
 *   <li>When an entry is evicted from the cache, {@code evictionCount} is incremented.
 *   <li>No stats are modified when a cache entry is invalidated or manually removed.

/**
 * A semi-persistent mapping from keys to values. Cache entries are manually added using {@link
 * #get(Object, Callable)} or {@link #put(Object, Object)}, and are stored in the cache until either
 * evicted or manually invalidated. The common way to build instances is using {@link CacheBuilder}.
 *
 * <p>Implementations of this interface are expected to be thread-safe, and can be safely accessed
 * by multiple concurrent threads.
 *

    void recordLoadException(long loadTime);

    /**
     * Records the eviction of an entry from the cache. This should only been called when an entry
     * is evicted due to the cache's eviction strategy, and not as a result of manual {@linkplain
     * Cache#invalidate invalidations}.
     */
    void recordEviction();

    /**

    CacheTesting.checkValidState(cache);
  }

  /**
   * Tests that when a single entry exceeds the segment's max weight, the new entry is immediately
   * evicted and nothing else.
   */
  public void testEviction_maxWeight_entryTooBig() {
    CountingRemovalListener<Integer, Integer> removalListener = countingRemovalListener();
    IdentityLoader<Integer> loader = identityLoader();

    void recordLoadException(long loadTime);

    /**
     * Records the eviction of an entry from the cache. This should only been called when an entry
     * is evicted due to the cache's eviction strategy, and not as a result of manual {@linkplain
     * Cache#invalidate invalidations}.
     */
    void recordEviction();

    /**