websocket admin connection to get query metric data

dart/packages/lbry/lib/src/client.dart

@@ -0,0 +1,49 @@
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:web_socket_channel/io.dart';
+import 'package:web_socket_channel/status.dart' as status;
+
+
+class Client {
+    String url;
+    IOWebSocketChannel channel;
+    StreamController<MetricDataPoint> _metricsController = StreamController.broadcast();
+    Stream<MetricDataPoint> get metrics => _metricsController.stream;
+
+    Client(this.url);
+
+    open() {
+        channel = IOWebSocketChannel.connect(this.url);
+        channel.stream.listen((message) {
+            Map data = json.decode(message);
+            _metricsController.add(
+                MetricDataPoint()
+                    ..search=data['search'] ?? 0
+                    ..search_time=data['search_time'] ?? 0
+                    ..resolve=data['resolve'] ?? 0
+                    ..resolve_time=data['resolve_time'] ?? 0
+            );
+        });
+    }
+
+    Future close() => channel.sink.close(status.goingAway);
+}
+
+
+class MetricDataPoint {
+    final DateTime time = DateTime.now();
+    int search = 0;
+    int search_time = 0;
+    int resolve = 0;
+    int resolve_time = 0;
+    int get avg_search => search_time > 0 ? (search_time/search).round() : 0;
+    int get avg_resolve => resolve_time > 0 ? (resolve_time/resolve).round() : 0;
+}
+
+
+cli() {
+    Client('ws://localhost:8181/')..open()..metrics.listen((m) {
+        print(m.search);
+    });
+}