Returns the package root of the current isolate, if any.
If the isolate is using a packageRoot or the isolate has not been
setup for package resolution, this getter returns null
, otherwise it
returns the package config URI.
Returns the package root of the current isolate, if any.
If the isolate is using a packageRoot or the isolate has not been
setup for package resolution, this getter returns null
, otherwise it
returns the package config URI.