function _matchesValue(allowedValue, value) {
    const wildcardIndex = allowedValue.indexOf('*');
    // If no wildcards, simply return whether strings are equal
    if (wildcardIndex === -1) {
        return allowedValue === value;
    }
    // Otherwise make sure substrings match expected substrings before
    // and after the wildcard
    const beginValue = allowedValue.substring(0, wildcardIndex);
    const endValue = allowedValue.substring(wildcardIndex + 1);
    return (value.startsWith(beginValue) && value.endsWith(endValue));
}
_matchesValue - compare two values to determine if they match
@param {string} allowedValue - an allowed value in a CORS rule;
   may contain wildcards
@param {string} value - value from CORS request
@return {boolean} - true/false