code: public String printResponseHeaders() {
  		StringBuilder sb = new StringBuilder();
  		HttpURLConnection http = http();
  		if (http != null) {
  			Map<String, List<String>> header = http.getHeaderFields();
  			for (String key : header.keySet()) {
  				for (String val : header.get(key)) {
  					sb.append(key).append(": ").append(val).append("\n");
  				}
  			}
  		}
  		return sb.toString();
  	}
docs: Print out the response headers for this resource.
  
  @return