@Override
    public boolean equals(@Nullable Object obj) {
        if (obj == null || obj.getClass() != HttpFileAttributes.class) {
            return false;
        }

        final HttpFileAttributes that = (HttpFileAttributes) obj;
        return length == that.length && lastModifiedMillis == that.lastModifiedMillis;
    }
Returns the last modified time represented as the number of milliseconds since the epoch.
core/src/main/java/com/linecorp/armeria/server/file/HttpFileAttributes.java