Delete forum threads
To delete a thread, you must perform the following:
    - Get an instance of the manager.
    Get an instance of the ForumsManager object. 
    - Get the specified thread.
    Get an instance of the thread. For more information, read For developers: Query forum threads. 
    - Mark the thread for deletion.
    To mark the thread to be deleted, call the DeleteThread method of the manager and pass the thread as an argument. 
    - Save the changes.
    To delete the thread, save the changes to the manager. 
NOTE: To delete multiple threads, query them and execute the code below for each thread.
NOTE: If you try to delete a thread that has posts in it, the posts will also get deleted.
Here is a code example: