pub unsafe extern "C" fn rocksdb_writebatch_delete_range_cf(
b: *mut rocksdb_writebatch_t,
column_family: *mut rocksdb_column_family_handle_t,
start_key: *const c_char,
start_key_len: usize,
end_key: *const c_char,
end_key_len: usize,
)