glog.go
func (l *Log) SetTraceLocation(location TraceLocation) {
	l.mu.Lock()
	defer l.mu.Unlock()
	l.traceLocation = location
}
func (l *Log) SetTraceLocation(location TraceLocation) {
	l.mu.Lock()
	defer l.mu.Unlock()
	l.traceLocation = location
}
// SetTaceLocation sets the location, file:N, which when encountered will cause logging to emit a stack trace