}
      return bufferedSource;
    }

    private Source source(Source source) {
      return new ForwardingSource(source) {
        long totalBytesRead = 0L;

        @Override public long read(Buffer sink, long byteCount) throws IOException {
          long bytesRead = super.read(sink, byteCount);
          // read() returns the number of bytes read, or -1 if this source is exhausted.