get_changed_uids
Description:
Returns an array of changed messages UIDs.
The returned array, the same as its content, is owned by the this.
Parameters:
| this | 
Returns:
| An array of changed UIDs. | 
Returns an array of changed messages UIDs.
The returned array, the same as its content, is owned by the this.
| this | 
| An array of changed UIDs. |