anchor.diff:  
           mc.throwExceptionIfClosed();
   
  - mc.close();
  +        mc.close();
           assertTrue(mc.isClosed());
           assertEquals(1, mc.performClose);
   
  
positive.code:         MyReferenceCounted rc = new MyReferenceCounted();
          rc.throwExceptionIfClosed();
  
   rc.closeable.close();
          try {
              rc.throwExceptionIfClosed();
  
   fail();
          } catch (IllegalStateException ignored) {
  
          }
  
negative.code:         assertEquals(1, rc.performRelease);
      }
  
      @Test
      public void reserveWhenClosed() {
          MyReferenceCounted rc = new MyReferenceCounted();
          assertEquals(1, rc.refCount());
  