Add auto logging of goroutine pid label (#19212)

* Add auto logging of goroutine pid label

This PR uses unsafe to export the hidden runtime_getProfLabel function from the
runtime package and then casts the result to a map[string]string.

We can then interrogate this map to get the pid label from the goroutine allowing
us to log it with any logging request.

Reference #19202

Signed-off-by: Andrew Thornton <art27@cantab.net>

modules/log/multichannel.go

@@ -72,6 +72,13 @@ func (l *MultiChannelledLogger) Log(skip int, level Level, format string, v ...i
 	if len(v) > 0 {
 		msg = ColorSprintf(format, v...)
 	}
+	labels := getGoroutineLabels()
+	if labels != nil {
+		pid, ok := labels["pid"]
+		if ok {
+			msg = "[" + ColorString(FgHiYellow) + pid + ColorString(Reset) + "] " + msg
+		}
+	}
 	stack := ""
 	if l.GetStacktraceLevel() <= level {
 		stack = Stack(skip + 1)