v1.6.8

中文迭代日志

• Fix: fix resume from breakpoint failed because of isAlive not guarantee on Network-thread. this closes #793
• Fix: fix resume from breakpoint failed, because of multi-thread update status very frequently and Messenger can't guarantee order. this refs #793, #764, #721, #769, #763, #761, #716
• Fix: do not crash user when a task has finished but the messenger still has messages, because it's fine for the user. this closes #562
• Fix: fix the callback error of 'it can't take a snapshot for the task xxx' when a user invokes pause very frequently.
• Fix: fix the case of process on the model is wrong which raise 416 each time when restarting it.