diff --git a/SuccessfulCodeTools.Tests/LowLevelHttpClientTests.cs b/SuccessfulCodeTools.Tests/LowLevelHttpClientTests.cs
new file mode 100644
index 0000000..af97a35
--- /dev/null
+++ b/SuccessfulCodeTools.Tests/LowLevelHttpClientTests.cs
@@ -0,0 +1,27 @@
+using SuccessfulCodeTools.LowLevelHttpClient;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace SuccessfulCodeTools.Tests
+{
+    public class LowLevelHttpClientTests
+    {
+        [Fact]
+        public void CheckLowLevelHttpClientConcurrency()
+        {
+            //Arrange
+            Parallel.ForEach(Enumerable.Range(1, 20), (e) =>
+             {
+                 var client = new CustomHttpClient(32455);
+                 client.SendAsync(new CustomHttpRequestMessage(HttpMethod.Get, "http://www.mocky.io/v2/5e546e473100004900eb31a5")).GetAwaiter().GetResult();
+             });
+            //Act
+            //Assert
+        }
+    }
+}
diff --git a/SuccessfulCodeTools/LowLevelHttpClient/CustomHttpClient.cs b/SuccessfulCodeTools/LowLevelHttpClient/CustomHttpClient.cs
index 11de1de..7bc6152 100644
--- a/SuccessfulCodeTools/LowLevelHttpClient/CustomHttpClient.cs
+++ b/SuccessfulCodeTools/LowLevelHttpClient/CustomHttpClient.cs
@@ -17,7 +17,7 @@ namespace SuccessfulCodeTools.LowLevelHttpClient
     {
         public int? OutgoingPort { get; set; }
         public KeyValueCollection<string, string> DefaultHeaders = new KeyValueCollection<string, string>();
-        private static ConcurrentDictionary<int, object> _dictionary = new ConcurrentDictionary<int, object>();
+        private static readonly ConcurrentDictionary<int, object> _dictionary = new ConcurrentDictionary<int, object>();
         public CustomHttpClient(int? outgoingPort = null)
         {
             OutgoingPort = outgoingPort;
@@ -40,6 +40,7 @@ namespace SuccessfulCodeTools.LowLevelHttpClient
                 tcp.Connect(remoteEndpoint);
                 tcp.LingerState.Enabled = false;
                 tcp.LingerState.LingerTime = 0;
+
                 tcp.SendTimeout = 500;
                 tcp.ReceiveTimeout = 1000;
                 // Send request headers
@@ -57,6 +58,8 @@ namespace SuccessfulCodeTools.LowLevelHttpClient
                 {
                     await stream.CopyToAsync(memory);
                     tcp.Client.Disconnect(true);
+                    stream.Close();
+                    tcp.Client.Close();
                     semphoreLock.Release();
                     return new CustomHttpResponseMessage(memory);
                 }