(Yaf >=1.0.0)
Yaf_Response_Abstract::clearBody — 清除已經設置的響應body
$key
清除已經設置的響應body
key
the content key, if you don't specific, then all contents will be cleared. 如果你沒選擇具體清除哪個key所對應的內容，那所有內容將被清除
注意: this parameter is introduced as of 2.2.0
注意:
this parameter is introduced as of 2.2.0