installState() method is used to determine whether or not a package has been installed.
ResourceFileManager.shared.installState(forPackage: KeymanPackage.Key) -> KeymanPackage.InstallationState
KeymanPackage.Keythat uniquely identifies the package.
Returns one of the following:
- The package has not been installed.
- KeymanEngine has been told to download the package, and the download is still pending.
- The package has been downloaded and temporarily opened, but installation is still pending.
- The package has been installed.