feat: add async stats api

Author: cnblogs-dudu

src/Enyim.Caching/MemcachedClient.cs

@@ -1204,6 +1204,27 @@ public ServerStats Stats(string type)
             return new ServerStats(results, _userIPv6);
         }
 
+        public Task<ServerStats> StatsAsync()
+        {
+            return StatsAsync(null);
+        }
+
+        public async Task<ServerStats> StatsAsync(string type)
+        {
+            var results = new Dictionary<EndPoint, Dictionary<string, string>>();
+
+            foreach (var node in _pool.GetWorkingNodes())
+            {
+                var cmd = _pool.OperationFactory.Stats(type);
+                await node.ExecuteAsync(cmd);
+                var endpoint = node.EndPoint;
+                lock (results)
+                    results[endpoint] = cmd.Result;
+            }
+
+            return new ServerStats(results, _userIPv6);
+        }
+
         /// <summary>
         /// Removes the specified item from the cache.
         /// </summary>

test/Enyim.Caching.Tests/MemcachedClienStatsTests.cs

@@ -1,6 +1,7 @@
 using Enyim.Caching.Configuration;
 using System;
 using System.Net;
+using System.Threading.Tasks;
 using Xunit;
 
 namespace Enyim.Caching.Tests
@@ -17,5 +18,17 @@ public void When_Getting_Uptime_Is_Successful()
             uptime = _client.Stats().GetUptime(ipEndPoint);
             Assert.True(uptime > TimeSpan.Zero);
         }
+
+        [Fact]
+        public async Task When_Getting_Uptime_Using_Async_Stats_Is_Successful()
+        {
+            var uptime = (await _client.StatsAsync()).GetUptime(new DnsEndPoint(_memcachedHost, _memcachedPort));
+            Assert.True(uptime > TimeSpan.Zero);
+
+            var ipEndPoint = new DnsEndPoint(_memcachedHost, _memcachedPort).GetIPEndPoint(false);
+            uptime = (await _client.StatsAsync()).GetUptime(ipEndPoint);
+            Console.WriteLine("uptime: " + uptime);
+            Assert.True(uptime > TimeSpan.Zero);
+        }
     }
 }

test/Enyim.Caching.Tests/MemcachedClientTestsBase.cs

@@ -2,13 +2,10 @@
 using Enyim.Caching.Memcached;
 using Enyim.Caching.Memcached.Results;
 using Enyim.Caching.Memcached.Transcoders;
-using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
 using System.Threading.Tasks;
 using Xunit;