private void releaseBuffers(Collection<ByteBuffer> toRelease, boolean isFromDataReader) {
    if (toRelease == null) return;
    for (ByteBuffer buf : toRelease) {
      releaseBuffer(buf, isFromDataReader);
    }
  }
Reads one compression block from the source; handles compression blocks read from
multiple ranges (usually, that would only happen with zcr).
Adds stuff to cachedBuffers, toDecompress and toRelease (see below what each does).
@param current BufferChunk where compression block starts.
@param cacheBuffers The result buffer array to add pre-allocated target cache buffer.
@param toDecompress The list of work to decompress - pairs of compressed buffers and the
                    target buffers (same as the ones added to cacheBuffers).
@param toRelease The list of buffers to release to zcr because they are no longer in use.
@param badEstimates The list of bad estimates that cannot be decompressed.
@return The resulting cache chunk.
ql/src/java/org/apache/hadoop/hive/ql/io/orc/encoded/EncodedReaderImpl.java