增加空实现

src/LiteIM.Core/NullImClient.cs

@@ -0,0 +1,61 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace LiteIM
+{
+    public class NullImClient : IImClient
+    {
+        public static NullImClient Instance { get; private set; } = new NullImClient();
+
+        public void ClearChanClient(string chan)
+        {
+
+        }
+
+        public IEnumerable<string> GetChanClientList(string chan)
+        {
+            yield break;
+        }
+
+        public IEnumerable<(string chan, long online)> GetChanList()
+        {
+            yield break;
+        }
+
+        public IEnumerable<string> GetChanListByClientId(string clientId)
+        {
+            yield break;
+        }
+
+        public long GetChanOnline(string chan)
+        {
+            return 0;
+        }
+
+        public IEnumerable<string> GetClientListByOnline()
+        {
+            yield break;
+        }
+
+        public bool HasOnline(string clientId)
+        {
+            return false;
+        }
+
+        public void JoinChan(string clientId, string chan)
+        {
+
+        }
+
+        public void LeaveChan(string clientId, params string[] chans)
+        {
+
+        }
+
+        public void LeaveChan(string clientId)
+        {
+
+        }
+    }
+}