public static Decompressor getDecompressor(CompressionCodec codec) {
    Decompressor decompressor = borrow(DECOMPRESSOR_POOL, codec.getDecompressorType());
    if (decompressor == null) {
      decompressor = codec.createDecompressor();
      LOG.debug("Got brand-new Decompressor [{}]", decompressor.getClass().getName());
    } else {
      LOG.debug("Got recycled Decompressor [{}]", decompressor.getClass().getName());
    }
    if (decompressor != null && !decompressor.getClass().isAnnotationPresent(DoNotPool.class)) {
      updateLeaseCount(decompressorCounts, decompressor, 1);
    }
    return decompressor;
  }
Get a {@link Decompressor} for the given {@link CompressionCodec} from the pool, or get a new
one if the pool is empty. Copied from hadoop-common without significant modification.
hbase-common/src/main/java/org/apache/hadoop/hbase/io/compress/CodecPool.java