Package-level declarations

A blocking game message consumer repository provider. This implementation will block any calling threads until an instance has been provided, after which all waiting threads will be notified.

A default game message consumer repository provider, returning the instance without any blocking or waiting.

A provider interface for game message consumer repositories. This is necessary as often times these consumers get loaded up quite late in the server boot process, and it'd be less than ideal to block server boot time behind something as trivial as this, when it isn't even going to be hit until the right moment.