if (connectionUser.candidateConnection() != null) {
      check(toClose == null)
      return ReusePlan(candidate)
    }

    // The call's connection was released.
    toClose?.closeQuietly()
    connectionUser.connectionReleased(candidate)
    connectionUser.connectionConnectionReleased(candidate)
    if (toClose != null) {
      connectionUser.connectionConnectionClosed(candidate)