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,
)