pub unsafe extern "C" fn rocksdb_approximate_sizes_cf(
    db: *mut rocksdb_t,
    column_family: *mut rocksdb_column_family_handle_t,
    num_ranges: c_int,
    range_start_key: *const *const c_char,
    range_start_key_len: *const usize,
    range_limit_key: *const *const c_char,
    range_limit_key_len: *const usize,
    sizes: *mut u64,
    errptr: *mut *mut c_char
)