Stop using the Hashable interface.

runtime/bin/websocket.dart

Index: runtime/bin/websocket.dart
diff --git a/runtime/bin/websocket.dart b/runtime/bin/websocket.dart
index a2658a54083596002d4c27dbfeb3133a65e7abe7..47e184a948b7c09a8fc465319ca7bd07fb959e3f 100644
--- a/runtime/bin/websocket.dart
+++ b/runtime/bin/websocket.dart
@@ -57,7 +57,7 @@ abstract class WebSocketHandler {
 /**
  * Server web socket connection.
  */
-abstract class WebSocketConnection implements Hashable {
+abstract class WebSocketConnection {
   /**
    * Sets the callback to be called when a message have been
    * received. The type on [message] is either [:String:] or
@@ -100,7 +100,7 @@ abstract class WebSocketConnection implements Hashable {
 /**
  * Client web socket connection.
  */
-abstract class WebSocketClientConnection implements Hashable {
+abstract class WebSocketClientConnection {
   /**
    * Creates a new web socket client connection based on a HTTP client
    * connection. The HTTP client connection must be freshly opened.