Capture the request time for performance data and support forced shutdown

pkg/analyzer_plugin/lib/channel/channel.dart

Index: pkg/analyzer_plugin/lib/channel/channel.dart
diff --git a/pkg/analyzer_plugin/lib/channel/channel.dart b/pkg/analyzer_plugin/lib/channel/channel.dart
index cf4730dc3c839cac406fc3a65b4a7ea65b380d5f..a524811d8519704f924886e2833a1ae5406bc622 100644
--- a/pkg/analyzer_plugin/lib/channel/channel.dart
+++ b/pkg/analyzer_plugin/lib/channel/channel.dart
@@ -51,6 +51,13 @@ abstract class ServerCommunicationChannel {
   void close();
 
   /**
+   * Cause the plugin to terminate as soon as possible. This should only be used
+   * when the plugin has failed to terminate after sending it a 'plugin.shutdown'
+   * request.
+   */
+  void kill();
+
+  /**
    * Listen to the channel for responses and notifications. If a response is
    * received, invoke the [onResponse] function. If a notification is received,
    * invoke the [onNotification] function. If an error is encountered while