v0.6.7

Optimize

[#884] optimize: unify timeout error
[#875] optimize(client): do not write body in stream mode if content-length is 0
[#871] optimize(http1): retry if the error is caused by broken pooled conn
[#860] optimize: modify judgment conditions when use retry and err = nil

Fix

[#876] fix: keep isTLS field in keepalive when reset the request

Tests

[#866] test(http1): fix retry test
[#804] test: add test for protocol http1

Chore

[#864] chore: remove wechat group in readme
[#817] chore(http1): remove duplicated code

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Thanks a lot to those community contributors who submit some pull requests for this version:
@a631807682