_2016-01-01_

 *  Fix: Don't do a health check on newly-created connections. This is
    unnecessary work that could put the client in an inconsistent state if the
    health check fails.


## Version 2.7.0

_2015-12-13_

 *  **Rewritten connection management.** Previously OkHttp's connection pool
    managed both idle and active connections for HTTP/2, but only idle
    connections for HTTP/1.x. With this update the connection pool manages both

import okhttp3.internal.isHealthy
import okhttp3.internal.tls.OkHostnameVerifier
import okio.Buffer

/**
 * A connection to a remote web server capable of carrying 1 or more concurrent streams.
 *
 * Connections are shared in a connection pool. Accesses to the connection's state must be guarded
 * by holding a lock on the connection.
 */
class RealConnection internal constructor(
  val taskRunner: TaskRunner,

 *  **There is no longer a global singleton connection pool.** In OkHttp 2.x,
    all `OkHttpClient` instances shared a common connection pool by default.
    In OkHttp 3.x, each new `OkHttpClient` gets its own private connection pool.
    Applications should avoid creating many connection pools as doing so
    prevents connection reuse. Each connection pool holds its own set of

        private final List<HttpURLConnection> connections = new ArrayList<>();
        private int currentIndex = 0;

        void addConnection(HttpURLConnection conn) {
            connections.add(conn);
        }

        @Override
        protected URLConnection openConnection(URL u) throws IOException {
            if (currentIndex < connections.size()) {
                return connections.get(currentIndex++);

 *
 *  4. If there's no existing connection, make a list of routes (which may require blocking DNS
 *     lookups) and attempt new connections to them. When failures occur, retries iterate the
 *     list of available routes.
 *
 * If the pool gains an eligible connection while DNS, TCP, or TLS work is in flight, this finder
 * will prefer pooled connections. Only pooled HTTP/2 connections are used for such de-duplication.
 *

_2020-03-08_

 *  Fix: Don't reuse a connection on redirect if certs match but DNS does not. For better
    locality and performance OkHttp attempts to use the same pooled connection across redirects and
    follow-ups. It independently shares connections when the IP addresses and certificates match,
    even if the host names do not. In 4.4.0 we introduced a regression where we shared a connection

 * limitations under the License.
 */
package okhttp3.internal.connection

/**
 * A policy for how the pool should treat a specific address.
 */
class AddressPolicy(
  /**
   * How many concurrent calls should be possible to make at any time.
   * The pool will routinely try to pre-emptively open connections to satisfy this minimum.
   * Connections will still be closed if they idle beyond the keep-alive but will be replaced.

plugins:
  - search
  - redirects:
      redirect_maps:
        # Redirect all feature pages to features/*
        'caching.md': 'features/caching.md'
        'calls.md': 'features/calls.md'
        'connections.md': 'features/connections.md'
        'events.md': 'features/events.md'
        'https.md': 'features/events.md'
        'interceptors.md': 'features/interceptors.md'
        'r8_proguard.md': 'features/r8_proguard.md'

     *
     * * **Stale pooled connections.** The [ConnectionPool] reuses sockets
     *   to decrease request latency, but these connections will occasionally time out.
     *
     * * **Unreachable proxy servers.** A [ProxySelector] can be used to
     *   attempt multiple proxy servers in sequence, eventually falling back to a direct
     *   connection.
     *

  }

  // Node/edge sets are the same, but node/edge connections differ due to edge type.
  @Test
  public void equivalent_directedVsUndirected() {
    graph.putEdge(N1, N2);

    MutableGraph<Integer> g2 = createGraph(oppositeType(edgeType));
    g2.putEdge(N1, N2);

    assertThat(graph).isNotEqualTo(g2);
  }

  // Node/edge sets and node/edge connections are the same, but directedness differs.
  @Test