DSN_RELAYED_FORMAT

(字串，0 - 256 個字元) 轉送通知的格式化字串。預設值為字串：

Your message to $a has been relayed to a messaging system which may not 
provide a final delivery confirmation

若要禁止轉換轉送通知，請為此選項指定空白字串。請注意，GATEWAY_NOTIFICATIONS必須設定為 1，才能使此選項生效。GATEWAY_NOTIFICATIONS=0 時，會忽略此選項。