code: public final void fromHttpResponse(LowLevelHttpResponse response, StringBuilder logger)
        throws IOException {
      clear();
      ParseHeaderState state = new ParseHeaderState(this, logger);
      int headerCount = response.getHeaderCount();
      for (int i = 0; i < headerCount; i++) {
        parseHeader(response.getHeaderName(i), response.getHeaderValue(i), state);
      }
      state.finish();
    }
docs: Puts all headers of the {@link LowLevelHttpResponse} into this {@link HttpHeaders} object.
  
  @param response Response from which the headers are copied
  @param logger {@link StringBuilder} to which logging output is added or {@code null} to disable
  logging
  @since 1.10