private static int valueToInt(String input, int defaultValue, String what) {
        if (input == null) return defaultValue;
        String trimmedInput = input.trim();
        if (trimmedInput.isEmpty()) {
            return defaultValue;
        }
        try {
            return Integer.parseInt(trimmedInput);
        } catch (Exception e) {
            log.error("{} failed: unable to parse '{}' as an integer.", what, trimmedInput, e);
            return defaultValue;
        }
    }
Represents a synonym for a configuration plus a conversion function. The conversion
function is necessary for cases where the synonym is denominated in different units
(hours versus milliseconds, etc.)
server-common/src/main/java/org/apache/kafka/server/config/ConfigSynonym.java