public String toSendString(){
		StringBuilder stringBuilder = new StringBuilder();
		
		stringBuilder.append(this.toHeadLine());
		stringBuilder.append("\r\n");
		
		Iterator<SipcHeader> iterator = this.getHeaders().iterator();
		while(iterator.hasNext()){
			stringBuilder.append(iterator.next().toSendString());
			stringBuilder.append("\r\n");
		}
		
		if (this.body != null && !this.hasHeader(SipcHeader.LENGTH)) {
			try {
				int len = this.body.toSendString().getBytes("UTF-8").length;
				if(len > 0){
					stringBuilder.append("L:" +len+ "\r\n");
				}
			} catch (UnsupportedEncodingException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
		}
		
		stringBuilder.append("\r\n");
		
		if (this.body != null) {
			stringBuilder.append(this.body.toSendString());
		}
		
		return stringBuilder.toString();
	}