mmap-buffer

(Mostly) safe wrapper for a fixed-size file-backed buffer.

Example

```rust use mmap_buffer::BackedBuffer;

fn main() -> Result<(), Box> { { let mut buf = BackedBuffer::::new(100, "test.data")?;

    // These changes will be reflected in the file
    buf[10] = -10;
    buf[20] = 27;
}

// Later, we can load the same array
let mut buf = BackedBuffer::<i32>::load("test.data")?;

assert_eq!(buf[10], -10);
assert_eq!(buf[20], 27);

Ok(())

} ```