print ubyte[] as (ascii) string

[eugene]

I suspect the question was asked somewhere before.
If so just give a link.

Anyway:

```d

class IoContext {
     ...
     ubyte[] buf;
     ...
     this(uint bufSize) {
         buf = new ubyte[bufSize];
     }
}

```

The buffer contains (ascii) string terminated with '\n'.
In order to print it not as an array of numbers (buf is 1024 
bytes long),
but as usual string I do

```d
char[] s = cast(char[])ioCtx.buf[0 .. 
strlen(cast(char*)ioCtx.buf.ptr) - 1];
// -1 is to eliminate terminating '\n'
writefln("got '%s' from '%s:%d'", s, client.addr, client.port);
```

Is there some more concise/elegant way to do that?

Of course, I could use old good printf() instead:
```d
printf(
     "got '%s' from '%s:%d'\n",
     ioCtx.buf.ptr,            // '\n' still there
     toStringz(client.addr),
     client.port
);
```

but I want to use D stdlib, not libc.