ImportManager allows a package to make some code available that can be run locally by a calling vat without requiring a remote round trip to the hosting vat. Remote code can indicate what function to run using a key.
Long term, we may want to import from a well-known repository, and manage version upgrades, but for now, we just import the code from the file system.
A package that wanted to export some code for clients to run in their own vat would import or define some functions, then call
const mgr = importManager();
return mgr.addExports(
{
'usefulFn', export1,
'helpfulFn', export2,
});
then it could pass strings like 'usefulFn' to clients, who could import the manager above, then call
const genericFn = importer.lookupImport(name);