private static void appendAttribute(CookieBuilder builder, String header,
                                        int keyStart, int keyEnd, int valueStart, int valueEnd) {
        final int length = keyEnd - keyStart;

        if (length == 4) {
            parse4(builder, header, keyStart, valueStart, valueEnd);
        } else if (length == 6) {
            parse6(builder, header, keyStart, valueStart, valueEnd);
        } else if (length == 7) {
            parse7(builder, header, keyStart, valueStart, valueEnd);
        } else if (length == 8) {
            parse8(builder, header, keyStart, valueStart, valueEnd);
        }
    }
Parse and store a key-value pair. First one is considered to be the
cookie name/value. Unknown attribute names are silently discarded.

@param keyStart
           where the key starts in the header
@param keyEnd
           where the key ends in the header
@param valueStart
           where the value starts in the header
@param valueEnd
           where the value ends in the header
core/src/main/java/com/linecorp/armeria/common/ClientCookieDecoder.java