net/http.(*persistConn).writeLoop goroutine leak in br

[RidRisR]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Run integration tests while enable goleak test

2. What did you expect to see? (Required)

No goroutine leak

3. What did you see instead (Required)

 Goroutine 708 in state select, with net/http.(*persistConn).writeLoop on top of the stack:
net/http.(*persistConn).writeLoop(0xc0020ff8c0)
        /usr/local/go/src/net/http/transport.go:2421 +0xe5
created by net/http.(*Transport).dialConn in goroutine 703
        /usr/local/go/src/net/http/transport.go:1777 +0x16f1

4. What is your TiDB version? (Required)