private static ImmutableMap<String, String> convertEnvInfoToMap(final EnvInfo envInfo) {
        return ImmutableMap.<String, String>builder()
                .put("maxReaders", Integer.toString(envInfo.maxReaders))
                .put("numReaders", Integer.toString(envInfo.numReaders))
                .put("lastPageNumber", Long.toString(envInfo.lastPageNumber))
                .put("lastTransactionId", Long.toString(envInfo.lastTransactionId))
                .put("mapAddress", Long.toString(envInfo.mapAddress))
                .put("mapSize", Long.toString(envInfo.mapSize))
                .build();
    }
Deletes {@link LmdbEnv} from the filesystem if it is already closed.
stroom-lmdb/src/main/java/stroom/lmdb/LmdbEnv.java