init

    fn init(block_size: u32, file_reader: *File.Reader, blocks: []u32, buffer: []u8) MsfStream {
        return .{
            .file_reader = file_reader,
            .next_read_pos = 0,
            .blocks = blocks,
            .block_size = block_size,
            .interface = .{
                .vtable = &.{ .stream = stream },
                .buffer = buffer,
                .seek = 0,
                .end = 0,
            },
            .err = null,
        };
    }