Move app/server to flipper-server-core

Summary: moved `app/src/server` to `flipper-server-core/src` and fixed any fallout from that (aka integration points I missed on the preparing diffs).

Reviewed By: passy

Differential Revision: D31541378

fbshipit-source-id: 8a7e0169ebefa515781f6e5e0f7b926415d4b7e9

desktop/flipper-server-core/src/comms/ClientConnection.tsx

@@ -0,0 +1,27 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import {ClientResponseType} from 'flipper-common';
+
+export enum ConnectionStatus {
+  ERROR = 'error',
+  CLOSED = 'closed',
+  CONNECTED = 'connected',
+  NOT_CONNECTED = 'not_connected',
+  CONNECTING = 'connecting',
+}
+
+export type ConnectionStatusChange = (status: ConnectionStatus) => void;
+
+export interface ClientConnection {
+  subscribeToEvents(subscriber: ConnectionStatusChange): void;
+  close(): void;
+  send(data: any): void;
+  sendExpectResponse(data: any): Promise<ClientResponseType>;
+}