toPlatformFile
Hands an export result back to FileKit, for a share sheet or a save dialog.
Android, Apple and the JVM only. A browser sink names a download rather than a file that already exists, so there is nothing to hand back there.
Throws
on a MediaSink.Uri this platform cannot parse. Which uris those are is per platform, since each one hands the string to its own URL type.
on MediaSink.Temporary, which is a request rather than a location. Read the resolved path off ExportStatus.Success.output instead.