panic: net/http: internal error: connCount underflow

panic: net/http: internal error: connCount underflow

goroutine 46 [running]:
net/http.(Transport).decConnsPerHost(0x1548ea0, 0x0, 0x0, 0xc000053ce0, 0x4, 0xc0000464e0, 0x12, 0x0)
/usr/local/go/src/net/http/transport.go:1447 +0x5a5
net/http.(persistConn).closeLocked(0xc0004c9200, 0xf682a0, 0xc00011eb90)
/usr/local/go/src/net/http/transport.go:2651 +0xf5
net/http.(persistConn).close(0xc0004c9200, 0xf682a0, 0xc00011eb90)
/usr/local/go/src/net/http/transport.go:2641 +0x85
net/http.(persistConn).readLoop.func1(0xc0004c9200, 0xc000122d50)
/usr/local/go/src/net/http/transport.go:2008 +0x45
net/http.(persistConn).readLoop(0xc0004c9200)
/usr/local/go/src/net/http/transport.go:2184 +0x12f8
created by net/http.(Transport).dialConn
/usr/local/go/src/net/http/transport.go:1708 +0xcb7

和设置了MaxConnsPerHost有关，这个是go的bug，我现在用的版本是:go version go1.15 darwin/amd64，依然没解决，操蛋啊！

准备抽时间看下源码到底咋回事。