Composite watched key names separated by comma, the key names is made up of: prefix, context and key name pattern
e.g., prefix: /config, context: /application, watched key: my.watch.key will return:
/config/application/my.watch.key
The returned watched key will be one key pattern, one or multiple specific keys e.g., 1) * 2) /application/abc*
3) /application/abc 4) /application/abc,xyz