@UnstableApi
    public VirtualHostBuilder setHeader(CharSequence name, Object value) {
        requireNonNull(name, "name");
        requireNonNull(value, "value");
        ensureNoPseudoHeader(name);
        defaultHeaders.setObject(name, value);
        return this;
    }
Sets the default HTTP header for an {@link HttpResponse} served by this {@link VirtualHost}.

<p>Note that the default header could be overridden if the same {@link HttpHeaderNames} are defined in
one of the followings:
<ul>
  <li>{@link ServiceRequestContext#additionalResponseHeaders()}</li>
  <li>The {@link ResponseHeaders} of the {@link HttpResponse}</li>
  <li>{@link VirtualHostServiceBindingBuilder#setHeader(CharSequence, Object)} or
      {@link VirtualHostAnnotatedServiceBindingBuilder#setHeader(CharSequence, Object)}</li>
</ul>
core/src/main/java/com/linecorp/armeria/server/VirtualHostBuilder.java