Puts on destination as a temp file, renames on
        the destination.

def copy(self, filename=None):
        """Puts on destination as a temp file, renames on
        the destination.
        """
        dst = os.path.join(self.dst_path, filename)
        src = os.path.join(self.src_path, filename)
        dst_tmp = os.path.join(self.dst_tmp, filename)
        self.put(src=src, dst=dst_tmp, callback=self.update_progress, confirm=True)
        self.rename(src=dst_tmp, dst=dst)