*/
    @Nonnull
    Map<String, String> getSystemProperties();

    /**
     * Returns the properly overlaid map of properties: system + user.
     */
    @Nonnull
    Map<String, String> getEffectiveProperties();

    /**
     * Returns the start time of the session.
     *
     * @return the start time as an Instant object, never {@code null}
     */
    @Nonnull
    Instant getStartTime();

    /**