text fileUri(path, flags)
Returns file path converted to a URI,
  used when “sharing” a file with another app, usually as Data URI or "android.intent.extra.STREAM" extra.
  Ensure to also enable the appropriate Grant flags where available.
Flags:
| Flag | Description | 
|---|---|
"a" | Convert path to a Automate content provider URI, the default | 
"d" | Convert path to a system document URI (Android 4.4+) | 
"f" | Convert path to a file URI | 
null if "d" flag conversion failed.