public Map<Version, FileRegistry> getFileRegistries() {
            return results.stream()
                    .collect(Collectors.toMap((prepareResult -> prepareResult.version),
                            (prepareResult -> prepareResult.fileRegistry)));
        }
Returns the host allocations resulting from this preparation.
configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionPreparer.java