lways returns 0 would be correct.
 In general, callers should only use this method if they'd be satisfied with
 treating the result as a boolean yes or no answer to the question "is there definitely
 data ready?".

 <p>Thirdly, the fact that a given number of bytes is "available" does not guarantee that a
 read or skip will actually read or skip that many bytes: they may read or skip fewer.

 <p>It is particularly important to realize that you <i>must not</i> use this method to
 size a container and assume 