code: @Override
      public Header getResponseFooter(String footerName) {
          if (footerName == null) {
              return null;
          } else {
              return getResponseTrailerHeaderGroup().getCondensedHeader(footerName);
          }
      }
docs: Gets the response footer associated with the given name.
  Footer name matching is case insensitive.
  <tt>null</tt> will be returned if either <i>footerName</i> is
  <tt>null</tt> or there is no matching footer for <i>footerName</i>
  or there are no footers available.  If there are multiple footers
  with the same name, there values will be combined with the ',' separator
  as specified by RFC2616.
  
  @param footerName the footer name to match
  @return the matching footer