/**
     * Singleton instance of CommandLibrary.
     * @type {CommandLibrary}
     * @readOnly
     * @private
     */

    /**
     * CommandLibrary constructor
     * @param {any} jibo Instance of jibo runtime
     * @param {boolean} [validate = true] Flag deteremining if CommandLibrary shoudl validate protocol, `false` used for testing
     */

    /**
     * Gets singleton instance of CommandLibrary.
     */

    /**
     * Destroy CommandLibrary and nullify its singleton
     */

    /**
     * Create a CommandConnector.
     * If there is alreayd a CommandConnector registered with taht id it will return that CommandConnector.
     */

    /**
     * Remove reference to CommandConnector.
     * If the given CommandConnector is the active it will be disconnected.
     */

    /**
     * Remove reference to CommandConnector by id.
     * If the given CommandConnector is the active it will be disconnected.
     */

    /**
     * Connect delegate to command library
     * private - only called by via CommandConnector.connect()
     * @private
     */

    /**
     * Returns a Promise that resolves on completion of entity engine update.
     * Convenience method for testing purposes
     * @return {Promise<void>} - Promise resolving on completion of entity engine update
     * @private
     */

    /**
     * Returns a entity Engine
     * Convenience method for testing purposes
     * @return {Engine} - entity engine of current command session
     * @private
     */

    /**
     * Method to pass commands.
     * @method CommandManager#onMessage
     * @param {Command} data
     * @private
     */

    /**
     * Handler for responses that could not be deliver, returned via a CommandConnector
     * @private
     */

    /**
     * Start a session.
     * @private
     */

    /**
     * Called by CommandConnector when a connection is lost, but a reconnect is desired.
     * Would get called in the case of connection disruption.
     * @private
     */

    /**
     * Called to disconnect current connection.
     * Sends disconnect request to currently active CommandConnector
     * @private
     */

    /**
     * End the current session and nullify active connection and connection proxy
     * @private
     */

    /**
     * Converts ACO into a Permissions object for use by the CommandLibrary
     * @private
     */

   /**
    * Create protocol validators for supported protocol versions
    * Will need to add validators for each supported protocol
    * @private
    */

   /**
    * Checks if data fits the protocol format of the current connection.
    * @private
    */

   /**
    * Checks if version matches active version, if not send appropriate response code
    * @private
    */

   /**
    * Checks if version string is incluced in set of supported protocols
    * @private
    */

   /**
    * Helper method to send acknowledgements
    * @private
    */