*/
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

func gridLogOnceIf(ctx context.Context, err error, id string, errKind ...any) {
	logger.LogOnceIf(ctx, "grid", err, id, errKind...)
}

// A Connection is a remote connection.
// There is no distinction externally whether the connection was initiated from
// this server or from the remote.
type Connection struct {
	// NextID is the next ID that can be used (atomic).
	NextID uint64

	// LastPong is last pong time (atomic)

  }

  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.
   */

    val pooled3 = routePlanner.planReusePooledConnection(this, routes)
    if (pooled3 != null) return pooled3.connection

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

    call.eventListener.connectionAcquired(call, connection)
    connection.connectionListener.connectionAcquired(connection, call)
    return connection
  }

    connection: Connection,
    route: Route,
    call: Call,
  ) {}

  /**
   * Invoked when a connection is released as no longer required.
   */
  open fun connectionClosed(connection: Connection) {}

  /**
   * Invoked when a call is assigned a particular connection.
   */
  open fun connectionAcquired(
    connection: Connection,
    call: Call,
  ) {}

  /**

    // 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)

  private fun waitForConnectionShutdown(connection: RealConnection?) {
    if (connection!!.isHealthy(false)) {
      Thread.sleep(100L)
    }
    if (connection.isHealthy(false)) {
      Thread.sleep(2000L)
    }
    if (connection.isHealthy(false)) {
      throw TimeoutException("connection didn't shutdown within timeout")
    }
  }

  /**

      call: Call,
      connection: Connection,
    ) {
      for (delegate in eventListeners) {
        delegate.connectionAcquired(call, connection)
      }
    }

    override fun connectionReleased(
      call: Call,
      connection: Connection,
    ) {
      for (delegate in eventListeners) {
        delegate.connectionReleased(call, connection)
      }
    }

	if err != nil {
		return err
	}

	// Wait for opened connection to be closed up to Shutdown timeout.
	return nil
}

// UseIdleTimeout configure idle connection timeout
func (srv *Server) UseIdleTimeout(d time.Duration) *Server {
	srv.IdleTimeout = d
	return srv
}

// UseReadTimeout configure connection request read timeout.
func (srv *Server) UseReadTimeout(d time.Duration) *Server {

   * That may happen later by the connection pool thread.
   */
  fun cancel()

  /**
   * Carries an exchange. This is usually a connection, but it could also be a connect plan for
   * CONNECT tunnels. Note that CONNECT tunnels are significantly less capable than connections.
   */
  interface Carrier {
    val route: Route

    fun trackFailure(