checkNotNull(from, "http response");
String meta = checkNotNull(from.getFirstHeaderOrNull(AtmosHeaders.META), AtmosHeaders.META);
Map<String, String> metaMap = Splitter.on(", ").withKeyValueSeparator('=').split(meta);
assert metaMap.size() >= 12 : String.format("Should be 12 entries in %s", metaMap);
byte[] md5 = metaMap.containsKey("content-md5") ? base16().lowerCase().decode(metaMap.get("content-md5")) : null;
return new SystemMetadata(md5, dateService.iso8601SecondsDateParse(checkNotNull(metaMap.get("atime"), "atime")),
dateService.iso8601SecondsDateParse(checkNotNull(metaMap.get("ctime"), "ctime")), checkNotNull(
metaMap.get("gid"), "gid"), dateService.iso8601SecondsDateParse(checkNotNull(metaMap.get("itime"),
"itime")), dateService.iso8601SecondsDateParse(checkNotNull(metaMap.get("mtime"), "mtime")),
Integer.parseInt(checkNotNull(metaMap.get("nlink"), "nlink")), checkNotNull(metaMap.get("objectid"),
"objectid"), checkNotNull(metaMap.get("objname"), "objname"), checkNotNull(metaMap.get("policyname"),