Add 'runnable' to Isolate service response

runtime/vm/service/service.md

-# Dart VM Service Protocol 3.0
+# Dart VM Service Protocol 3.3
 
 > Please post feedback to the [observatory-discuss group][discuss-list]
 
-This document describes of _version 3.0_ of the Dart VM Service Protocol. This
+This document describes of _version 3.3_ of the Dart VM Service Protocol. This
 protocol is used to communicate with a running Dart Virtual Machine.
 
 To use the Service Protocol, start the VM with the *--observe* flag.
 The VM will start a webserver which services protocol requests via WebSocket.
 It is possible to make HTTP (non-WebSocket) requests,
 but this does not allow access to VM _events_ and is not documented
 here.
 
 The Service Protocol uses [JSON-RPC 2.0][].
 
@@ skipping 1797 matching lines @@
   string number;
 
   // A name identifying this isolate. Not guaranteed to be unique.
   string name;
 
   // The time that the VM started in milliseconds since the epoch.
   //
   // Suitable to pass to DateTime.fromMillisecondsSinceEpoch.
   int startTime;
 
+  // Is the isolate in a runnable state?
+  bool runnable;
+
   // The number of live ports for this isolate.
   int livePorts;
 
   // Will this isolate pause when exiting?
   bool pauseOnExit;
 
   // The last pause event delivered to the isolate. If the isolate is
   // running, this will be a resume event.
   Event pauseEvent;
 
@@ skipping 478 matching lines @@
 }
 ```
 
 ## Revision History
 
 version | comments
 ------- | --------
 1.0 | initial revision
 2.0 | Describe protocol version 2.0.
 3.0 | Describe protocol version 3.0.  Added UnresolvedSourceLocation.  Added Sentinel return to getIsolate.  Add AddedBreakpointWithScriptUri.  Removed Isolate.entry. The type of VM.pid was changed from string to int.  Added VMUpdate events.  Add offset and count parameters to getObject() and offset and count fields to Instance. Added ServiceExtensionAdded event.
-
+3.1 | Add the getSourceReport RPC.  The getObject RPC now accepts offset and count for string objects.  String objects now contain length, offset, and count properties.
+3.2 | Isolate objects now include the runnable bit and many debugger related RPCs will return an error if executed on an isolate before it is runnable.
+3.3 | A patched protocol version used in stable 1.14.2, containing the addition in 3.2 but not the addition in 3.1.
 
 [discuss-list]: https://groups.google.com/a/dartlang.org/forum/#!forum/observatory-discuss