<pre class="notranslate">for example, one might want to solve <a href="https://golang.org/issue/4357" rel="nofollow">issue #4357</a> with this.

a test program: <a href="http://play.golang.org/p/gyk1yehoTp" rel="nofollow">http://play.golang.org/p/gyk1yehoTp</a>

i think we can treat a nil byte slice as the signal.</pre>
<pre class="notranslate">Time.MarshalJSON also encodes uninitialized time.Time values.

It would be better if the encoding was guarded with IsZero() to avoid returning
meaningless times.</pre>