private void addToBitmapPool(PreFillType toAllocate, Bitmap bitmap) {
        // The pool may not move sizes to the front of the LRU on put. Do a get here to make sure the size we're adding
        // is at the front of the queue so that the Bitmap we're adding won't be evicted immediately.
        if (seenTypes.add(toAllocate)) {
          Bitmap fromPool = bitmapPool.get(toAllocate.getWidth(), toAllocate.getHeight(),
              toAllocate.getConfig());
            if (fromPool != null) {
                bitmapPool.put(fromPool);
            }
        }

        bitmapPool.put(bitmap);
    }
Attempts to allocate {@link Bitmap}s and returns {@code true} if there are more
{@link Bitmap}s to allocate and {@code false} otherwise.
core/src/main/java/com/bumptech/glide/load/engine/prefill/BitmapPreFillRunner.java