Stream blocks of timeline events over the service protocol

runtime/vm/service/service.md

Index: runtime/vm/service/service.md
diff --git a/runtime/vm/service/service.md b/runtime/vm/service/service.md
index 25753208bc3056a418952f04b2f73f8aa2ce5921..7e6c7f0ac2670fb66b3d9971f9aba04752881528 100644
--- a/runtime/vm/service/service.md
+++ b/runtime/vm/service/service.md
@@ -772,6 +772,7 @@ Isolate | IsolateStart, IsolateRunnable, IsolateExit, IsolateUpdate, ServiceExte
 Debug | PauseStart, PauseExit, PauseBreakpoint, PauseInterrupted, PauseException, Resume, BreakpointAdded, BreakpointResolved, BreakpointRemoved, Inspect, None
 GC | GC
 Extension | Extension
+Timeline | TimelineEvents
 
 Additionally, some embedders provide the _Stdout_ and _Stderr_
 streams.  These streams allow the client to subscribe to writes to
@@ -1213,6 +1214,11 @@ class Event extends Response {
   // This is provided for the Extension event.
   ExtensionData extensionData [optional];
 
+  // An array of TimelineEvents
+  //
+  // This is provided for the TimelineEvents event.
+  TimelineEvent[] timelineEvents [optional];
+
   // Is the isolate paused at an await, yield, or yield* statement?
   //
   // This is provided for the event kinds:
@@ -2365,6 +2371,15 @@ class Success extends Response {
 
 The _Success_ type is used to indicate that an operation completed successfully.
 
+### TimelineEvent
+
+```
+class TimelineEvent {
+}
+```
+
+An _TimelineEvent_ is an arbitrary map that contains a [Trace Event Format](https://docs.google.com/document/d/1CvAClvFfyA5R-PhYUmn5OOQtYMH4h6I0nSsKchNAySU/preview) event.
+
 ### TypeArguments
 
 ```