code: @Trivial
      @Override
      public Enumeration<String> getAttributeNames() {
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
              Tr.debug(tc, "Getting attribute names");
          }
          return Collections.enumeration(this.attributes.keySet());
      }
docs: /*
  @see javax.servlet.ServletRequest#getAttributeNames()