doh: buffers not flushed?

[jelu]

One query timed-out but HTTP/2 return codes said all responses received.

[Status] Command line: dnsperf -n 2000 -m doh -T 1 -c 1 -d doh.csv -Q 1000 -S 1 -O doh-method=POST -O doh-uri=https://dns.google/dns-query -s dns.google -t 10
[Status] Sending queries (to 8.8.4.4:443)
[Status] Started at: Thu May 11 10:00:21 2023
[Status] Stopping after 2000 runs through file
1683792022.208230: 971.944468
1683792023.209306: 1001.921932
[Timeout] Query timed out: msg id 1191
[Status] Testing complete (end of file)

Statistics:

  Queries sent:         2000
  Queries completed:    1999 (99.95%)
  Queries lost:         1 (0.05%)

  Response codes:       NOERROR 1999 (100.00%)
  Average packet size:  request 37, response 53
  Run time (s):         2.026278
  Queries per second:   986.537879

  Average Latency (s):  0.008476 (min 0.004251, max 0.020062)
  Latency StdDev (s):   0.001934

Connection Statistics:

  Reconnections:        0 (0.00% of 1 connections)

  Average Latency (s):  0.020142 (min 0.020142, max 0.020142)

DNS-over-HTTPS statistics:

  HTTP/2 return codes:  200: 2000