public ServerBuilder clientAddressMapper(
            Function<? super ProxiedAddresses, ? extends InetSocketAddress> clientAddressMapper) {
        this.clientAddressMapper = requireNonNull(clientAddressMapper, "clientAddressMapper");
        return this;
    }
Sets a {@link Function} to use when determining the client address from {@link ProxiedAddresses}.
If not set, the {@link ProxiedAddresses#sourceAddress()}} is used as a client address.
core/src/main/java/com/linecorp/armeria/server/ServerBuilder.java