vendor-specific methods or add experimental features. See [PROTOCOL.agent] section 3.8.
</span><span class="c1"></span>	<span class="c1">// If agent extensions are unsupported entirely this method MUST return an
</span><span class="c1"></span>	<span class="c1">// ErrExtensionUnsupported error. Similarly, if just the specific extensionType in
</span><span class="c1"></span>	<span class="c1">// the request is unsupported by the agent then ErrExtensionUnsupported MUST be
</span><span class="c1"></span>	<span c