Bug 1581963 - [devtools] Add a new trait to control the use of the bulk API for the performance panel r=devtools-reviewers,devtools-backward-compat-reviewers,profiler-reviewers,nchevobbe,mstange

Differential Revision: https://phabricator.services.mozilla.com/D245460

devtools/server/actors/root.js

@@ -144,6 +144,9 @@ class RootActor extends Actor {
       // Contact Holger Benl (hbenl) to make sure the VS Code extension is
       // updated.
       supportsEnableWindowGlobalThreadActors: true,
+      // @backward-compat { version 140 } Use the bulk API to transfer the
+      // performance profile data.
+      useBulkTransferForPerformanceProfile: true,
     };
   }