public RedirectConfigBuilder allowProtocols(SessionProtocol... protocols) {
        requireNonNull(protocols, "protocols");
        return allowProtocols(ImmutableSet.copyOf(protocols));
    }
Sets the {@link SessionProtocol}s that are allowed for automatic redirection.
Only {@link SessionProtocol#HTTP} and {@link SessionProtocol#HTTPS} can be set.

<p>When the allowed {@link SessionProtocol}s are not set, {@link SessionProtocol#HTTPS} is set
by default. If the {@link WebClient} is created <b>with</b> a base URI that has
{@link SessionProtocol#HTTP}, {@link SessionProtocol#HTTP} is also set.
core/src/main/java/com/linecorp/armeria/client/redirect/RedirectConfigBuilder.java