+ Such marker follows the first non-escaped TAB. For more information
+ see avast-protocol(5)
+
+ We observed two cases:
+ -> SCAN /file
+ <- /file [E]0.0 Error 13 Permission denied
+ <- 451 SCAN Engine error 13 permission denied
+
+ -> SCAN /file
+ <- /file… [E]3.0 Error 41120 The file is a decompression bomb
+ <- /file… [+]2.0
+ <- /file… [+]2.0 0 Eicar Test Virus!!!
+ <- 200 SCAN OK
+
+ If the scanner returns 4xx, DEFER is a good decision, combined
+ with a panic log entry, to get the admin's attention.
+
+ If the scanner returns 200, we reject it as malware, if found any,
+ or, in case of an error, we set the malware message to the error
+ string.
+
+ Some of the >= 42000 errors are message related - usually some
+ broken archives etc, but some of them are e.g. license related.
+ Once the license expires the engine starts returning errors for
+ every scanning attempt. I¹ have the full list of the error codes
+ but it is not a public API and is subject to change. It is hard
+ for me to say what you should do in case of an engine error. You
+ can have a “Treat * unscanned file as infection” policy or “Treat
+ unscanned file as clean” policy. ¹) Jakub Bednar
+
+ */
+