* Add tests for Database and DatabaseQuery
* Add tests for DatabaseReference
* Add tests for DataEventType
* Add tests for DataSnapshot
* Add tests for MutableData
* Add tests for ServerValue
* Add tests for TransactionResult
* Fix CI for CocoaPods
* Fix CI for SPM and style
* Improve readability
* Fix CI for tvOS
* Refactor type checking
* Fix comments
Add unsurfaced parameter names and shorten async lines
* Fix switch conditional evaluates to a constant
* Fix type checking
* Shorten switch statement
* Add to SPM tests