183     json::OStream J(OS);  in write()  local
184     J.objectBegin();  in write()
185     J.attributeBegin("traceEvents");  in write()
186     J.arrayBegin();  in write()
193       J.object([&] {  in write()
194         J.attribute("pid", Pid);  in write()
195         J.attribute("tid", int64_t(Tid));  in write()
196         J.attribute("ts", StartUs);  in write()
198           J.attribute("cat", E.Name);  in write()
199           J.attribute("ph", "b");  in write()
200           J.attribute("id", 0);  in write()
202           J.attribute("ph", "X");  in write()
203           J.attribute("dur", DurUs);  in write()
205         J.attribute("name", E.Name);  in write()
207           J.attributeObject("args", [&] {  in write()
209               J.attribute("detail", E.Metadata.Detail);  in write()
211               J.attribute("file", E.Metadata.File);  in write()
213               J.attribute("line", E.Metadata.Line);  in write()
219         J.object([&] {  in write()
220           J.attribute("pid", Pid);  in write()
221           J.attribute("tid", int64_t(Tid));  in write()
222           J.attribute("ts", StartUs + DurUs);  in write()
223           J.attribute("cat", E.Name);  in write()
224           J.attribute("ph", "e");  in write()
225           J.attribute("id", 0);  in write()
226           J.attribute("name", E.Name);  in write()
274       J.object([&] {  in write()
275         J.attribute("pid", Pid);  in write()
276         J.attribute("tid", int64_t(TotalTid));  in write()
277         J.attribute("ph", "X");  in write()
278         J.attribute("ts", 0);  in write()
279         J.attribute("dur", DurUs);  in write()
280         J.attribute("name", "Total " + Total.first);  in write()
281         J.attributeObject("args", [&] {  in write()
282           J.attribute("count", int64_t(Count));  in write()
283           J.attribute("avg ms", int64_t(DurUs / Count / 1000));  in write()
292       J.object([&] {  in write()
293         J.attribute("cat", "");  in write()
294         J.attribute("pid", Pid);  in write()
295         J.attribute("tid", int64_t(Tid));  in write()
296         J.attribute("ts", 0);  in write()
297         J.attribute("ph", "M");  in write()
298         J.attribute("name", Name);  in write()
299         J.attributeObject("args", [&] { J.attribute("name", arg); });  in write()
308     J.arrayEnd();  in write()
309     J.attributeEnd();  in write()
314     J.attribute("beginningOfTime",  in write()
319     J.objectEnd();  in write()