@Nullable
        private static String handleThrowable(@Nullable Throwable cause) {
            if (cause == null) {
                return null;
            }
            cause = Exceptions.peel(cause);
            final String message = cause.getMessage();
            return message != null ? cause.getClass().getSimpleName() + ": " + message
                                   : cause.getClass().getSimpleName();
        }
A {@link RequestLog} component of a log message.
core/src/main/java/com/linecorp/armeria/server/logging/AccessLogComponent.java