@Override
  public InputStream asInputStream() throws IOException {
    // TODO, ideally, would like not to bring guava just for this
    final CountingInputStream input = new CountingInputStream(delegate.asInputStream());
    count = input::getCount;
    return input;
  }
{@link Body} implementation that keeps track of how many bytes are read.
micrometer/src/main/java/feign/micrometer/MeteredBody.java