ByteBuffer await() {
      try {
        return result.get();
      } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
        return throwFatalException(e);
      } catch (ExecutionException e) {
        return throwFatalException(e);
      }
    }
A segment of the storage file that threads can update in parallel, and can be flushed to disk when all threads are
done writing to it.
planetiler-core/src/main/java/com/onthegomap/planetiler/collection/ArrayLongLongMapMmap.java