static void closeQuietly(/*Auto*/Closeable closeable) {
    if (closeable != null) {
      try {
        closeable.close();
      } catch (RuntimeException rethrown) {
        throw rethrown;
      } catch (Exception ignored) {
      }
    }
  }
Deletes the contents of {@code dir}. Throws an IOException if any file
could not be deleted, or if {@code dir} is not a readable directory.
core/src/main/java/com/bumptech/glide/disklrucache/Util.java