track pack downloads
Refactoring LogType so as not to rely on instantiation order.

Signed-off-by: bolte-17 <bolte.17@gmail.com>
Change constructor to not read from uninitialized field
Lazy initialization of static field using holder class idiom (Effective Java, Item 71)

Signed-off-by: bolte-17 <bolte.17@gmail.com>