fix: 修复空指针和类型转换问题

kunlong-luo

2023-02-02 8f2ce95165f90e51d41b083610d00ae346f3a852

 src/main/java/com/genersoft/iot/vmp/gb28181/task/ISubscribeTask.java

@@ -2,8 +2,9 @@

import javax.sip.DialogState;

/**
 * @author lin
 */
public interface ISubscribeTask extends Runnable{
    void stop();

    DialogState getDialogState();
}