to use IPv4 as a backup if it looks like IPv6 might be
failing.
</li>
+
+ <li> <!-- CL 31726 -->
+ The <a href="/pkg/net/http/#Transport"><code>Transport</code></a>
+ no longer reads a byte of a non-nil
+ <a href="/pkg/net/http/#Request.Body"><code>Request.Body</code></a>
+ when the
+ <a href="/pkg/net/http/#Request.ContentLength"><code>Request.ContentLength</code></a>
+ is zero to determine whether the <code>ContentLength</code>
+ is actually zero or just undefined.
+ To explicitly signal that a body has zero length,
+ either set it to <code>nil</code>, or set it to the new value
+ <a href="/pkg/net/http/#NoBody"><code>NoBody</code></a>.
+ The new <code>NoBody</code> value is intended for use by <code>Request</code>
+ constructor functions; it is used by
+ <a href="/pkg/net/http/#NewRequest"><code>NewRequest</code></a>.
+ </li>
</ul>
</dd>