pub unsafe extern "C" fn partial_merge_callback<F: MergeFn, PF: MergeFn>( raw_cb: *mut c_void, raw_key: *const c_char, key_len: size_t, operands_list: *const *const c_char, operands_list_len: *const size_t, num_operands: c_int, success: *mut u8, new_value_length: *mut size_t) -> *mut c_char
