char peekAsKey() {
            final char c = path.charAt(index);
            switch (c) {
                case '\0':
                    return KEY_PARAMETER;
                case '*':
                    return KEY_CATCH_ALL;
                default:
                    return c;
            }
        }
Splits this {@link RoutingTrie.Node} into two by the given index of the path.
core/src/main/java/com/linecorp/armeria/server/RoutingTrieBuilder.java