We may bump to 0.2 version as soon as possible

[x] The 0.1 version has an error not reported to the user #54
[x] There is a type of error using #54
[x] Lack of defense against fd attacks, need a timeout error #54 #57
[x] Some users want to be able to support event stream output instead of callback，0.2 should support both programming modes at the same time #58
[x] Let user control turn protocol on and off, breaking change #62
[x] May need to support each protocol has their own codec, and does not require the same structure(trait object) #63
[x] Add poll API to all protocol handle, to allow users to customize some stream tasks in the handle #65

release 0.2.0-alpha.1

[x] Abstract transport layer #76
[ ] Maybe there are other problems, let us wait and see in the evolution process.