Document the Inspect event in the service protocol.

runtime/vm/service/service.md

 # Dart VM Service Protocol 3.0
 
 > Please post feedback to the [observatory-discuss group][discuss-list]
 
 This document describes of _version 3.0_ 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,
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 If the client is not subscribed to the stream, the _103_ (Stream already
 subscribed) error code is returned.
 
 The _streamId_ parameter may have the following published values:
 
 streamId | event types provided
 -------- | -----------
 VM | VMUpdate
 Isolate | IsolateStart, IsolateRunnable, IsolateExit, IsolateUpdate
 Debug | PauseStart, PauseExit, PauseBreakpoint, PauseInterrupted, PauseException, Resume, BreakpointAdded, BreakpointResolved, BreakpointRemoved, Inspect
 GC | GC

[turnidge, 2015/11/23 23:54:40]

You should add the event type here as well.

[rmacnak, 2015/11/24 00:55:59]

It's already listed here as part of the Debug stream.

 
 Additionally, some embedders provide the _Stdout_ and _Stderr_
 streams.  These streams allow the client to subscribe to writes to
 stdout and stderr.
 
 streamId | event types provided
 -------- | -----------
 Stdout | WriteEvent
 Stderr | WriteEvent
 
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   Frame topFrame [optional];
 
   // The exception associated with this event, if this is a
   // PauseException event.
   @Instance exception [optional];
 
   // An array of bytes, encoded as a base64 string.
   //
   // This is provided for the WriteEvent event.
   string bytes [optional];
+
+  // The argument passed to dart:developer.inspect.
+  //
+  // This is provided for the Inspect event.
+  @Instance inspectee [optional];
 }
 ```
 
 An _Event_ is an asynchronous notification from the VM. It is delivered
 only when the client has subscribed to an event stream using the
 [streamListen](#streamListen) RPC.
 
 For more information, see [events](#events).
 
 ### EventKind
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   // An unresolved breakpoint has been resolved for an isolate.
   BreakpointResolved,
 
   // A breakpoint has been removed.
   BreakpointRemoved,
 
   // A garbage collection event.
   GC,
 
   // Notification of bytes written, for example, to stdout/stderr.
-  WriteEvent
+  WriteEvent,
+
+  // Notification from dart:developer.inspect.
+  Inspect
 }
 ```
 
 Adding new values to _EventKind_ is considered a backwards compatible
 change. Clients should ignore unrecognized events.
 
 ### Field
 
 ```
 class @Field extends @Object {
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 ## 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.
 
 
 [discuss-list]: https://groups.google.com/a/dartlang.org/forum/#!forum/observatory-discuss