@Nullable
    private static String computeValue(String header, int valueStart, int valueEnd) {
        return isValueDefined(valueStart, valueEnd) ? header.substring(valueStart, valueEnd) : null;
    }
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