private Closeables() {}

  /**
   * Closes a {@link Closeable}, with control over whether an {@code IOException} may be thrown.
   * This is primarily useful in a finally block, where a thrown exception needs to be logged but
   * not propagated (otherwise the original exception will be lost).
   *
   * <p>If {@code swallowIOException} is true then we never throw {@code IOException} but merely log
   * it.
   *
   * <p>Example:
   *

  }

  /**
   * Returns the empty immutable set. Preferred over {@link Collections#emptySet} for code
   * consistency, and because the return type conveys the immutability guarantee.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings({"unchecked"}) // fully variant implementation (never actually produces any Es)
  public static <E> ImmutableSet<E> of() {

  @Override
  final UnmodifiableIterator<Cell<R, C, V>> cellIterator() {
    throw new AssertionError("should never be called");
  }

  @Override
  final Spliterator<Cell<R, C, V>> cellSpliterator() {
    throw new AssertionError("should never be called");
  }

  @Override
  public ImmutableCollection<V> values() {
    return (ImmutableCollection<V>) super.values();
  }

1. Config ingestion (inputs to the system)
1. Config translation
1. Config serving (XDS)

### Config Ingestion

Istio reads from over 20 different resources types, and aggregates them together to build the proxy configuration. These resources can be sourced from Kubernetes (via watches), files, or over xDS; Kubernetes is by far the most common usage, though.

Primarily for historical reasons, ingestion is split into a few components.

   * <p>Note in particular that an equivalence wrapper is never equal to the object it wraps.
   *
   * <pre>{@code
   * equiv.wrap(obj).equals(obj) // always false
   * }</pre>
   *
   * @since 10.0
   */
  public static final class Wrapper<T extends @Nullable Object> implements Serializable {
    /*
     * Equivalence's type argument is always non-nullable: Equivalence<Number>, never

   * <p>Note in particular that an equivalence wrapper is never equal to the object it wraps.
   *
   * <pre>{@code
   * equiv.wrap(obj).equals(obj) // always false
   * }</pre>
   *
   * @since 10.0
   */
  public static final class Wrapper<T extends @Nullable Object> implements Serializable {
    /*
     * Equivalence's type argument is always non-nullable: Equivalence<Number>, never

   * loaded entries; it will never contain null keys or values.
   *
   * <p>Caches loaded by a {@link CacheLoader} will issue a single request to {@link
   * CacheLoader#loadAll} for all keys which are not already present in the cache. All entries
   * returned by {@link CacheLoader#loadAll} will be stored in the cache, over-writing any

    return response
  }

  /**
   * Returns a new source that writes bytes to [cacheRequest] as they are read by the source
   * consumer. This is careful to discard bytes left over when the stream is closed; otherwise we
   * may never exhaust the source stream and therefore not complete the cached response.
   */
  @Throws(IOException::class)
  private fun cacheWritingResponse(
    cacheRequest: CacheRequest?,

   * loaded entries; it will never contain null keys or values.
   *
   * <p>Caches loaded by a {@link CacheLoader} will issue a single request to {@link
   * CacheLoader#loadAll} for all keys which are not already present in the cache. All entries
   * returned by {@link CacheLoader#loadAll} will be stored in the cache, over-writing any

                "uid": "${datasource}"
              },
              "expr": "pilot_conflict_outbound_listener_tcp_over_current_tcp{app=\"istiod\"}",
              "format": "time_series",
              "hide": false,
              "intervalFactor": 1,
              "legendFormat": "Outbound Listeners (tcp over current tcp)",
              "refId": "C"
            }
          ],
          "title": "Conflicts",