_validateConnection (conn) {
    if (!conn.isOpen()) {
      return false
    }

    const maxConnectionLifetime = this._config.maxConnectionLifetime
    const lifetime = Date.now() - conn.creationTimestamp
    if (lifetime > maxConnectionLifetime) {
      return false
    }

    return true
  }
Check that a connection is usable
@return {boolean} true if the connection is open
@access private