src/vs/workbench/services/workingCopy/common/workingCopyService.ts/WorkingCopyService/has
class WorkingCopyService:	has(resourceOrIdentifier: URI | IWorkingCopyIdentifier): boolean {
		if (URI.isUri(resourceOrIdentifier)) {
			return this.mapResourceToWorkingCopies.has(resourceOrIdentifier);
		}

		return this.mapResourceToWorkingCopies.get(resourceOrIdentifier.resource)?.has(resourceOrIdentifier.typeId) ?? false;
	}