**Describe the situation**

The author implemented it but enabled only for DiskS3.
CC @excitoon 
new_key = keys[0].substr(0, pos) + "." + std::to_string(index) + (pos == std::string::npos ? "" : keys[0].substr(pos));
                    ++index;
                }
                while (checkIfObjectExists(client_auth.client, client_auth.uri.bucket, new_key));
                keys.push_back(new_key);
            }
            else
                throw Exception(
                    ErrorCodes::BAD_ARGUMENTS,
                    "Object in bucket {} with key {} already exists. If you want to overwrite it, enable setting s3_truncate_on_insert, if you "
                    "want to create a new file on each insert, enable setting s3_create_new_file_on_insert",
                    client_auth.uri.bucket,
                    keys.back());
        }
        return std::make_shared<StorageS3Sink>(
            format_name,
            sample_block,
            local_context,
            format_settings,
            chosen_compression_method,
            client_auth.client,
            client_auth.uri.bucket,
            keys.back(),
            min_upload_part_size,
            upload_part_size_multiply_factor,
            upload_part_size_multiply_parts_count_threshold,
            max_single_part_upload_size);
    }
}
void StorageS3::truncate(const ASTPtr & , const StorageMetadataPtr &, ContextPtr local_context, TableExclusiveLockHolder &)