history_buffer = string_sprintf("%s%s", history_buffer, dkim_history_buffer);
history_buffer = string_sprintf("%spdomain %s\n", history_buffer, dmarc_used_domain);
history_buffer = string_sprintf("%s%s", history_buffer, dkim_history_buffer);
history_buffer = string_sprintf("%spdomain %s\n", history_buffer, dmarc_used_domain);