Context is everything

This release adds the ability to include context to each service call. For example, you might want to include certain information about the user that is triggering the event or page view. You can now specify a context object on the Metrics service itself, that will be included across all calls.

For example:

const currentUserName = Ember.get(this, 'currentUser.fullName'); // 'Derek Zoolander'
Ember.set(this, 'metrics.context.userName', currentUserName);
Ember.get(this, 'metrics').trackPage({ page: 'page/1' }); // { userName: 'Derek Zoolander', page: 'page/1' }

Thanks to @opsb for implementing this feature.