is it need to maintain http 2.x in sdk

[githubcheng2978]

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is it neccesary to maintain http in sdk?.
2.x http longpoll was replace by grpc, so http only was use to get access token synchronize,
i think use grpc to achieve the same goal，and reduce code complexity

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[KomachiSion]

also persistent instance registered by http for now.

and should check whether some other api use http still