public InetSocketAddress socketAddress(SessionProtocol protocol) {
        return delegate.socketAddress(protocol);
    }
Returns the {@link InetSocketAddress} of the specified {@link SessionProtocol} for the {@link Server}.

@throws IllegalStateException if the {@link Server} is not started or
                              it did not open a port for the specified {@link SessionProtocol}.
junit4/src/main/java/com/linecorp/armeria/testing/junit4/server/ServerRule.java