call a native method to destroy that peer.
 Even then, it's better to provide an explicit <code>close</code> method (and implement
 <code><a href="../../../reference/java/io/Closeable.html">Closeable</a></code>), and insist that callers manually dispose of instances. This
 works well for something like files, but less well for something like a <code>BigInteger</code>
 where typical calling code would have to deal with lots of temporaries. Unfortunately,
 code that creates lots of temporaries is the worst ki