private synchronized void ensurePoolSizeInvariant() {
    if (mIgnoreHardCap) {
      return;
    }
    Preconditions.checkState(!isMaxSizeSoftCapExceeded() || mFree.mNumBytes == 0);
  }
Ensure pool size invariants. The pool must either be below the soft-cap OR it must have no free
values left
imagepipeline/src/main/java/com/facebook/imagepipeline/memory/BasePool.java