This code adds the ability to write statistics to disk.
On-disk format:
uint32_t Size;
struct {
uint32_t metadata_type;
uint32_t offset; /* offset into this file */
} metadata_metadata[Size];
* each metadata_metadata entry corresponds to a metadata
stored in the file.
Signed-off-by: Raphael S. Carvalho <raphaelsc@cloudius-systems.com>