Record separator is being lost after string cast

[Kadir Erdem Demir via Digitalmars-d-learn]

I am opening a .gz file and reading it chunk by chunk for 
uncompressing it.

The data in the uncompressed file is like : aRSbRScRSd, There are 
record separators(ASCII code 30) between each record(records in 
my dummy example a,b,c).

    File file = File(mylog.gz, "r");
    auto uc = new UnCompress();
    foreach (ubyte[] curChunk; file.byChunk(4096*1024))
    {
        auto uncompressed = cast(string)uc.uncompress(curChunk);
        writeln(uncompressed);
        auto stringRange = uncompressed.splitLines();
        foreach (string line; stringRange)
        {
            ***************** Do something with line

The result of the code above is: abcd unfortunately record 
separators(ASCII 30) are missing.

I realized by examining the data record separators are missing 
after I cast ubyte[] to string.

Now I have two questions :

Urgent one (my boss already a little disturbed I started the task 
with D I need to solve this): What should I change in the code to 
keep record separator?

Second one : How can I write the code above without for loops? I 
want to read gz file line by line.

A more general and understandable code for first question :

    ubyte[] temp = [ 65, 30, 66, 30, 67];
    writeln(temp);
    string tempStr = cast(string) temp;
    writeln (tempStr);

Result is : ABC which is not desired.

Thanks
Kadir Erdem