@Override
    public int hashCode() {
        int result = tables.hashCode();
        result = 31 * result + (verify ? 1 : 0);
        return result;
    }
Convert a string value to a quoted value suitable for use in a config string.
<p>
Adds double quotes before and after, and adds backslash-escapes to any double quotes that was contained in the
string.  A null pointer will produce the special unquoted string null that the config library will convert back
to a null pointer.

@param input the String to be escaped
@return an escaped String
messagebus/src/main/java/com/yahoo/messagebus/routing/RoutingSpec.java