Feature Request: include mirror stats in /debug/querylogz output

[maxenglander]

Feature Description

Mirror query stats are included in Logstats.

vitess/go/vt/vtgate/logstats/logstats.go

Lines 57 to 59 in 5d439cd

	MirrorSourceExecuteTime time.Duration
	MirrorTargetExecuteTime time.Duration
	MirrorTargetError error

However, they do not appear in /debug/querylogz output:

vitess/go/vt/vtgate/querylogz.go

Lines 62 to 81 in 5d439cd

	querylogzTmpl = template.Must(template.New("example").Funcs(querylogzFuncMap).Parse(`
	<tr class="{{.ColorLevel}}">
	<td>{{.Method}}</td>
	<td>{{.ContextHTML}}</td>
	<td>{{.EffectiveCaller}}</td>
	<td>{{.ImmediateCaller}}</td>
	<td>{{.SessionUUID}}</td>
	<td>{{.StartTime | stampMicro}}</td>
	<td>{{.EndTime | stampMicro}}</td>
	<td>{{.TotalTime.Seconds}}</td>
	<td>{{.PlanTime.Seconds}}</td>
	<td>{{.ExecuteTime.Seconds}}</td>
	<td>{{.CommitTime.Seconds}}</td>
	<td>{{.StmtType}}</td>
	<td>{{.SQL | .Parser.TruncateForUI | unquote | cssWrappable}}</td>
	<td>{{.ShardQueries}}</td>
	<td>{{.RowsAffected}}</td>
	<td>{{.ErrorStr}}</td>
	</tr>
	`))

Add them to query log output.

Use Case(s)

This is useful for being able to see how query mirroring is performing.