code: @Override
      public List<String> getHeaders() {
          List<HeaderField> hdrs = this.message.getAllHeaders();
          List<String> values = new ArrayList<String>(hdrs.size());
          for (HeaderField header : hdrs) {
              values.add(header.getName());
          }
          return values;
      }
docs: /*
  @see com.ibm.websphere.http.HttpResponse#getHeaders()