Failed to archive JPEG (ArchiveMember): Invalid UTF-8 sequence (at index 1)

[Ki Rill]

Please, help me solve the annoying error above. I've been 
refactoring and rewriting code for my archive utility called 
[zippo](https://github.com/rillki/zippo) and I face this error 
when it tries to archive a JPEG image.

I tracked it down to the following function that helps me add a 
new member to `ZipArchive`.

```D
void zipAddArchiveMember(ref ZipArchive zip, in string file) {
     import std.conv: to;
     import std.file: readText;
     import std.string: representation;

     ArchiveMember member = new ArchiveMember();
     member.name = file;
     writefln("%s", file);
     member.expandedData(file.readText().dup().representation());
     member.compressionMethod = CompressionMethod.deflate;
     zip.addMember(member);
}
```

Am I missing something?