net/http: TestTransportEventTrace_h2 fails with "expected substring "WroteRequest: {Err:<nil>}" in output."

[mikioh]

See https://build.golang.org/log/641eac826e7b0a6183e1b0ce7c6bb75e572c73e0
Looks like netDial succeeds but httptrace.GotConnInfo is empty, strange.

--- FAIL: TestTransportEventTrace_h2 (0.01s)
    transport_test.go:3305: expected substring "WroteRequest: {Err:<nil>}" in output.
    transport_test.go:3326: Output:
        Getting conn for dns-is-faked.golang:64428 ...
        DNS start: {Host:dns-is-faked.golang}
        DNS done: {Addrs:[{IP:127.0.0.1 Zone:}] Err:<nil> Coalesced:false}
        ConnectStart: Connecting to tcp 127.0.0.1:64428 ...
        ConnectDone: connected to tcp 127.0.0.1:64428 = <nil>
        got conn: {Conn:<nil> Reused:false WasIdle:false IdleTime:0s}
        got conn: {Conn:0xc4202d8000 Reused:false WasIdle:true IdleTime:2562047h47m16.854775807s}
        first response byte
        first response byte
FAIL
FAIL    net/http    14.351s

[mikioh]

Not only dragonfly but linux-ppc64le-buildlet:

• https://build.golang.org/log/5daa1b9c90074e62c170b0a32b0f3c94082cf274
• https://build.golang.org/log/d1cb531a2f326371e4571c0ddd73cc3d63c061fc

[mikioh]

and linux-amd64-nocgo:

• https://build.golang.org/log/522117f60aa5c3f1e2c00fc7f5f684c88ccf30e2

[bradfitz]

I have a fix.

[gopherbot]

CL https://golang.org/cl/23254 mentions this issue.

[gopherbot]

CL https://golang.org/cl/23235 mentions this issue.