*  **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

     *
     * * **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.
     *

password             (string)    MQTT password
qos                  (number)    set the quality of service priority, defaults to '0'
keep_alive_interval  (duration)  keep-alive interval for MQTT connections in s,m,h,d
reconnect_interval   (duration)  reconnect interval for MQTT connections in s,m,h,d
queue_dir            (path)      staging dir for undelivered messages e.g. '/home/events'

      MockResponse(body = "XXX"),
    )
    val connections: MutableList<RealConnection?> = ArrayList()
    val localClient =
      client.newBuilder().eventListener(
        object : EventListener() {
          override fun connectionAcquired(
            call: Call,
            connection: Connection,
          ) {
            connections.add(connection as RealConnection)
          }
        },

 * international domain names work everywhere. For example, "σ" encodes as "xn--4xa". The encoded
 * string is not human readable, but can be used with classes like [InetAddress] to establish
 * connections.
 *
 * ## Why another URL model?
 *
 * Java includes both [java.net.URL][URL] and [java.net.URI][URI]. We offer a new URL
 * model to address problems that the others don't.
 *

* Bump GCE debian image to container-v1-3-v20160604 ([#26851](https://github.com/kubernetes/kubernetes/pull/26851), [@zmerlynn](https://github.com/zmerlynn))
* Option to enable http2 on client connections. ([#25280](https://github.com/kubernetes/kubernetes/pull/25280), [@timothysc](https://github.com/timothysc))

    // Play it back.
    val connection = connect(peer)
    connection.newStream(headerEntries("a", "android"), false)
    connection.withLock {
      if (!connection.isHealthy(System.nanoTime())) {
        throw ConnectionShutdownException()
      }
    }
    connection.writePing()
    connection.shutdown(ErrorCode.PROTOCOL_ERROR)
    assertThat(connection.openStreamCount()).isEqualTo(1)

    assertThat(connectionAcquired2.connection).isSameAs(
      connectionAcquired1.connection,
    )
  }

  @Test
  fun multipleConnectionsFoundForSingleCall() {
    server.enqueue(
      MockResponse.Builder()
        .code(301)
        .addHeader("Location", "/foo")
        .addHeader("Connection", "Close")
        .build(),
    )
    server.enqueue(

            log.trace("Release session " + usage + " " + this);
        }

        if ( usage == 0 ) {
            if ( log.isDebugEnabled() ) {
                log.debug("Usage dropped to zero, release connection " + this.transport);
            }
            synchronized ( this ) {
                if ( this.transportAcquired.compareAndSet(true, false) ) {
                    this.transport.release();
                }

	public fun connectEnd (Lokhttp3/Connection;Lokhttp3/Route;Lokhttp3/Call;)V
	public fun connectFailed (Lokhttp3/Route;Lokhttp3/Call;Ljava/io/IOException;)V
	public fun connectStart (Lokhttp3/Route;Lokhttp3/Call;)V
	public fun connectionAcquired (Lokhttp3/Connection;Lokhttp3/Call;)V
	public fun connectionClosed (Lokhttp3/Connection;)V
	public fun connectionReleased (Lokhttp3/Connection;Lokhttp3/Call;)V