code: private void renderAttribute(InternalStringBuilder buf, String name, String value)
      {
          assert (name != null);
          if (value == null)
              return;
  
          buf.append(" ");
          buf.append(name);
          buf.append("=\"");
          buf.append(value);
          buf.append("\"");
      }
docs: This method will write append an attribute value to a InternalStringBuilder.
  The method assumes that the attr is not <code>null</code>.  If the
  value is <code>null</code> the attribute will not be appended to the
  <code>InternalStringBuilder</code>.