Add documentation to recommend naming convention for wake lock tags

     * as the user moves between applications and doesn't require a special permission.

     * </p>

     *

     * <p>

     * Recommended naming conventions for tags to make debugging easier:

     * <ul>

     * <li>use a unique prefix delimited by a colon for your app/library (e.g.

     * gmail:mytag) to make it easier to understand where the wake locks comes

     * from. This namespace will also avoid collision for tags inside your app

     * coming from different libraries which will make debugging easier.

     * <li>use constants (e.g. do not include timestamps in the tag) to make it

     * easier for tools to aggregate similar wake locks. When collecting

     * debugging data, the platform only monitors a finite number of tags,

     * using constants will help tools to provide better debugging data.

     * <li>avoid using Class#getName() or similar method since this class name

     * can be transformed by java optimizer and obfuscator tools.

     * <li>avoid wrapping the tag or a prefix to avoid collision with wake lock

     * tags from the platform (e.g. *alarm*).

     * <li>never include personnally identifiable information for privacy

     * reasons.

     * </ul>

     * </p>

     *

     * @param levelAndFlags Combination of wake lock level and flag values defining

     * the requested behavior of the WakeLock.

     * @param tag Your class name (or other tag) for debugging purposes.

         * cost of that work can be accounted to the application.

         * </p>

         *

         * <p>

         * Make sure to follow the tag naming convention when using WorkSource

         * to make it easier for app developers to understand wake locks

         * attributed to them. See {@link PowerManager#newWakeLock(int, String)}

         * documentation.

         * </p>

         *

         * @param ws The work source, or null if none.

         */

        public void setWorkSource(WorkSource ws) {