static ResponseLogLevelMapper of(Class<? extends Throwable> clazz, LogLevel logLevel) {
        requireNonNull(clazz, "clazz");
        requireNonNull(logLevel, "logLevel");
        return log -> {
            final Throwable t = log.responseCause();
            if (t == null) {
                return null;
            }
            final Class<? extends Throwable> throwableClass = t.getClass();
            if (clazz.isAssignableFrom(throwableClass)) {
                return logLevel;
            }
            return null;
        };
    }
Creates a new {@link ResponseLogLevelMapper} which returns the specified {@link LogLevel} if the given
class of {@link RequestLog#responseCause()} is assignable from the specified {@link Throwable} class.
core/src/main/java/com/linecorp/armeria/common/logging/ResponseLogLevelMapper.java