h3. Plugins need a specific metadata model

Each application will have its own model for plugins. Much of this model will be common across applications but there will always be issues specific to a particular applications’s plugins. Some of the issues that need to be taken into consideration:

* Plugin dependencies

 * href="https://github.com/lukas-krecan/future-converter">Future Converter</a>.)
 *
 * <h3>Extension</h3>
 *
 * If you want a class like {@code FluentFuture} but with extra methods, we recommend declaring your
 * own subclass of {@link ListenableFuture}, complete with a method like {@link #from} to adapt an
 * existing {@code ListenableFuture}, implemented atop a {@link ForwardingListenableFuture} that

 *
 * ## OkHttpClients Should Be Shared
 *
 * OkHttp performs best when you create a single `OkHttpClient` instance and reuse it for all of
 * your HTTP calls. This is because each client holds its own connection pool and thread pools.
 * Reusing connections and threads reduces latency and saves memory. Conversely, creating a client
 * for each request wastes resources on idle pools.
 *

                // Empty implementation
            }
        };

        CrawlerPooledObjectFactory<TestComponent> factory2 = createFactory("singletonComponent", listener);

        // Each factory retains its own configuration
        assertEquals("testComponent", factory.getComponentName());
        assertNull(factory.getOnDestroyListener());

        assertEquals("singletonComponent", factory2.getComponentName());

   * WritableByteChannel)}:
   *
   * <ol>
   *   <li>Use sendfile(2) or equivalent. Requires that both the input channel and the output
   *       channel have their own file descriptors. Generally this only happens when both channels
   *       are files or sockets. This performs zero copies - the bytes never enter userspace.

    directedGraph.putEdge(N1, N2);
    directedGraph.putEdge(N1, N3);
    directedGraph.putEdge(N2, N3);
    directedGraph.addNode(N4);

    // the above graph is its own transitive closure
    MutableGraph<Integer> expectedClosure = GraphBuilder.directed().allowsSelfLoops(true).build();
    expectedClosure.putEdge(N1, N2);
    expectedClosure.putEdge(N1, N3);
    expectedClosure.putEdge(N2, N3);

      /*
       * The result has the same type argument we started with. We just couldn't express EnumSet<E>
       * or ImmutableEnumSet<E> along the way because our own <E> isn't <E extends Enum<E>>.
       *
       * We are also performing a safe covariant cast to change <? extends E> to <E>.
       */
      @SuppressWarnings("unchecked")

      - [kube-controller-manager:](#kube-controller-manager)
      - [kubelet:](#kubelet-1)
      - [kube-proxy:](#kube-proxy)
      - [kubeadm:](#kubeadm)
      - [kubectl:](#kubectl-1)
      - [add-ons:](#add-ons)
      - [kube-scheduler:](#kube-scheduler)
      - [Other deprecations:](#other-deprecations)
    - [API Change](#api-change-6)
      - [New API types/versions:](#new-api-typesversions)

     * longer be the case.)
     *
     * javax.naming.Name and java.util.concurrent.Delayed might work, but
     * they're fairly obscure, we've invented our own interface and class.
     */
    Interface a = new Impl();
    Interface b = new Impl();
    ImmutableSortedSet<Interface> set = ImmutableSortedSet.of(a, b);
    Object[] unused1 = set.toArray();

   *     Storage overview</a> to select an appropriate temporary directory (perhaps {@code
   *     context.getCacheDir()}), and create your own directory under that. (For example, you might
   *     use {@code new File(context.getCacheDir(), "directoryname").mkdir()}, or, if you need an