I need to be able to create a large "dummy" file (around 1 GB) quickly. I am currently looping over a byte array and appending it to the file, but this results in may separate disk hits:

```
NSFileHandle *handle = [NSFileHandle fileHandleForWritingAtPath:self.path];
[handle seekToEndOfFile];

while (shouldContinue)
{
     NSData *dummyData = [self buildDummyData];
     [handle writeData:dummyData];
}

```

But this takes around 7 seconds to complete. I would like it to complete in less than 1 second. Is there a way to create a file and allocate its size without needing to append bytes to it?