Currently the default implementation of IEMFEditingContext.dispose() does:

this.getDomain().getResourceSet().getResources().forEach(Resource::unload);

This is costly both in CPU and RAM for no benefit: it will iterate on the content of all resources, compute the proxy URI for every element (which can allocate a lot of long strings and use lots of memory), and then... nothing. Nothing/nobody will ever use the ResourceSet in question after that.
Unloading is only useful to force all elements to become proxies so they are properly re-resolved afterwards, but in our case its all for nothing.

On my machine, this explicit unload takes about 820ms, compared to the ~2200ms needed to load the resource set.
It's not blocking anyone as this is only done once nobody is connected to the editing context, but it's still burning CPU and increasing memory pressure for no benefit.