the core type of <code>T</code> is called <code>bytestring</code>.
</p>

<p>
Examples of interfaces with <code>bytestring</code> core types:
</p>

<pre>
interface{ int }                          // int (same as ordinary core type)
interface{ []byte | string }              // bytestring
interface{ ~[]byte | myString }           // bytestring
</pre>

<p>

    that `tag()` now returns null if the request has no tag. Previously this would return the
    request itself.
 *  New: `Headers.Builder.addAll(Headers)`.
 *  New: `ResponseBody.create(MediaType, ByteString)`.
 *  New: Embed R8/ProGuard rules in the jar. These will be applied automatically by R8.
 *  Fix: Release the connection if `Authenticator` throws an exception.