code: protected void deflate() throws IOException {
          // Android-changed: output all available compressed data (b/4005091)
          int len = 0;
          while ((len = def.deflate(buf, 0, buf.length)) > 0) {
            out.write(buf, 0, len);
          }
      }
docs: Writes next block of compressed data to the output stream.
  @throws IOException if an I/O error has occurred