Method isACK

SIP/SIPMessage.h:116–116

	bool isCANCEL() const { return !strcmp(smGetMethodName(),"CANCEL"); }
	bool isBYE() const { return !strcmp(smGetMethodName(),"BYE"); }
	bool isACK() const { return !strcmp(smGetMethodName(),"ACK"); }
	// Has the message been initialized yet?  We always add callid first thing, so check that.
	bool smIsEmpty() const { return msmContent.empty() && msmCallId.empty(); }
};