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发布v7.4.0,新增部分qvs API

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Merge pull request qiniu#479 from qiniu/hugo

[qvs]add stopStream and delete check argument

Merge pull request qiniu#488 from qiniu/neiko

Neiko - example for issue

Merge pull request qiniu#488 from qiniu/neiko

Neiko - example for issue

7.2.28[ci skip]

7.2.26

Merge pull request qiniu#450 from qiniu/p_v7.2.25

7.2.25 [ci skip]

v 7.2.24