public int getPending() {
    return (int) pendingCountAll.get();
  }
Returns the number of enqueued items that have not been dequeued yet.
<p>
NOTE: this may be larger than the initial capacity because each writer thread can buffer items into a batch and
each reader thread might be reading items from a batch.
planetiler-core/src/main/java/com/onthegomap/planetiler/worker/WorkQueue.java