assertNotSame(buf, duplicate);
assertEquals(buf.position(), duplicate.position());
assertEquals(buf.limit(), duplicate.limit());
assertEquals(buf.isReadOnly(), duplicate.isReadOnly());
assertEquals(buf.isDirect(), duplicate.isDirect());
assertEquals(buf.order(), duplicate.order());
assertEquals(buf.capacity(), duplicate.capacity());
assertContentEquals(buf, duplicate);
// duplicate's position, mark, and limit should be independent to
// buf