Add db.AsyncLock

Src/Asp.NetCore2/SqlSugar/Abstract/SugarProvider/SqlSugarProvider.cs

@@ -1632,6 +1632,11 @@ namespace SqlSugar
         #endregion
 
         #region Other
+        public Task<SugarAsyncLock> AsyncLock(int timeOutSeconds = 30)
+        {
+            var result = new SugarAsyncLock(this);
+            return result.AsyncLock(timeOutSeconds);
+        }
         public DynamicBuilder DynamicBuilder() 
         {
             return new DynamicBuilder(this.Context);

Src/Asp.NetCore2/SqlSugar/Abstract/SugarProvider/SqlSugarScopeProvider.cs

@@ -114,7 +114,10 @@ namespace SqlSugar
         }
 
         #region  API
-
+        public Task<SugarAsyncLock> AsyncLock(int timeOutSeconds = 30)
+        {
+            return ScopedContext.AsyncLock(timeOutSeconds);
+        }
         public SugarActionType SugarActionType { get => ScopedContext.SugarActionType; set => ScopedContext.SugarActionType = value; }
         public MappingTableList MappingTables { get => ScopedContext.MappingTables; set => ScopedContext.MappingTables = value; }
         public MappingColumnList MappingColumns { get => ScopedContext.MappingColumns; set => ScopedContext.MappingColumns = value; }

Src/Asp.NetCore2/SqlSugar/Interface/ISqlSugarClient.cs

@@ -46,6 +46,7 @@ namespace SqlSugar
         #endregion
 
         #region Other methods
+        Task<SugarAsyncLock> AsyncLock(int timeOutSeconds = 30);
         DynamicBuilder DynamicBuilder();
         void Tracking<T>(T  data) where T : class, new();
         void Tracking<T>(List<T> data) where T : class, new();

Src/Asp.NetCore2/SqlSugar/SqlSugarClient.cs

@@ -1189,6 +1189,10 @@ namespace SqlSugar
         #endregion
 
         #region Helper
+        public Task<SugarAsyncLock> AsyncLock(int timeOutSeconds = 30)
+        {
+            return this.Context.AsyncLock(timeOutSeconds);
+        }
         public SplitTableContext SplitHelper<T>() where T:class,new()
         {
             return this.Context.SplitHelper<T>();

Src/Asp.NetCore2/SqlSugar/SqlSugarScope.cs

@@ -851,5 +851,9 @@ namespace SqlSugar
         {
             ScopedContext.RemoveConnection(configId);
         }
+        public Task<SugarAsyncLock> AsyncLock(int timeOutSeconds=30)
+        {
+            return ScopedContext.AsyncLock(timeOutSeconds);
+        }
     }
 }

Src/Asp.NetCore2/SqlSugar/Utilities/SugarAsyncLock.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace SqlSugar
+{
+    public class SugarAsyncLock : IDisposable
+    {
+        static  readonly SemaphoreSlim SemaphoreSlim =new SemaphoreSlim(1);
+
+ 
+        public SugarAsyncLock(SqlSugarProvider db) 
+        {
+
+        }
+         
+        public async Task<SugarAsyncLock> AsyncLock(int timeOutSeconds)
+        {
+            TimeSpan timeout = TimeSpan.FromSeconds(timeOutSeconds);
+            await SemaphoreSlim.WaitAsync(timeout);
+            return this;
+        }
+
+        public void Dispose()
+        {
+            SemaphoreSlim.Release();
+        }
+    }
+}