code: private boolean isMessageCompressed() {
          String contentEncoding = m_request.getHeader(HttpDefs.CONTENT_ENCODING);
          if (contentEncoding != null) {
              if (!contentEncoding.equalsIgnoreCase("gzip")) {
                  throw new IllegalArgumentException("Unsupported Content-Encoding: " + contentEncoding);
              }
              return true;
          }
          return false;
      }
docs: If Content-Encoding is included, verify that we support it and return true.