*/
interface Connection {
  /** Returns the route used by this connection. */
  fun route(): Route

  /**
   * Returns the socket that this connection is using. Returns an
   * [SSL socket][javax.net.ssl.SSLSocket] if this connection is HTTPS. If this is an HTTP/2
   * connection the socket may be shared by multiple concurrent calls.
   */
  fun socket(): Socket

 * When making TLS connections with multiple [connection specs](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-connection-spec/), these are attempted in sequence until the TLS handshake succeeds.

### [Connections](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-connection/)

When you request a URL with OkHttp, here's what it does:

    if (pooled3 != null) return pooled3.connection

    connection.withLock {
      connectionPool.put(connection)
      user.acquireConnectionNoEvents(connection)
    }

    user.connectionAcquired(connection)
    user.connectionConnectionAcquired(connection)
    return connection
  }

  override fun trackFailure(
    call: RealCall,
    e: IOException?,

      }
    }
    return null
  }

  fun put(connection: RealConnection) {
    connection.assertLockHeld()

    connections.add(connection)
//    connection.queueEvent { connectionListener.connectEnd(connection) }
    scheduleCloser()
  }

  /**
   * Notify this pool that [connection] has become idle. Returns true if the connection has been
   * removed from the pool and should be closed.

   * - Both request discover no existing connection. They both make a connection.
   * - The first request "wins the race".
   * - The second request discovers it "lost the race" and closes the connection it just opened.
   * - The second request uses the coalesced connection from request1.
   * - The coalesced connection is violently closed after servicing the first request.

 * **ExchangeFinder** chooses which connection carries each exchange. Where possible it will use the same connection for all exchanges in a single call. It prefers reusing pooled connections over establishing new connections.      

#### Per-Connection Locks

        URLConnection connection1 = handler.openConnection(url1);
        URLConnection connection2 = handler.openConnection(url2);

        assertNotNull(connection1, "First connection should not be null.");
        assertNotNull(connection2, "Second connection should not be null.");
        assertTrue(connection1 instanceof NtlmHttpURLConnection, "First connection should be wrapped.");

    assertLockNotHeld()

    val connection = this.connection
    if (connection != null) {
      connection.assertLockNotHeld()
      val toClose: Socket? =
        connection.withLock {
          // Sets this.connection to null.
          releaseConnectionNoEvents()
        }
      if (this.connection == null) {
        toClose?.closeQuietly()

        throw new TransportException("All connection attempts failed");
    }

    /**
     * Checks if the specified transport is contained in the connection pool
     * @param trans the transport to check for
     * @return whether (non-exclusive) connection is in the pool
     */
    public boolean contains(final SmbTransport trans) {
        cleanup();
        return this.connections.contains(trans);
    }

  override fun connectionReleased(connection: Connection) {
  }

  override fun connectionConnectionAcquired(connection: RealConnection) {
  }

  override fun connectionConnectionReleased(connection: RealConnection) {
  }

  override fun connectionConnectionClosed(connection: RealConnection) {
  }

  override fun noNewExchanges(connection: RealConnection) {
  }