增加内存流池MemoryStreamPool，减少MemoryStream的分配和回收

diff --git a/NewLife.Core/Collections/IPool.cs b/NewLife.Core/Collections/IPool.cs
index aedc251..637ded4 100644
--- a/NewLife.Core/Collections/IPool.cs
+++ b/NewLife.Core/Collections/IPool.cs
@@ -33,10 +33,6 @@ namespace NewLife.Collections
         /// <summary>字符串构建器池</summary>
         public static IPool<StringBuilder> StringBuilder { get; set; } = new StringBuilderPool();
 
-        ///// <summary>借助一个字符串构建器</summary>
-        ///// <returns></returns>
-        //public static StringBuilder GetStringBuilder() => Pool.StringBuilder.Get();
-
         /// <summary>归还一个字符串构建器到对象池</summary>
         /// <param name="sb"></param>
         /// <param name="requireResult">是否需要返回结果</param>
@@ -98,7 +94,7 @@ namespace NewLife.Collections
             return buf;
         }
 
-        /// <summary>内存流构建器池</summary>
+        /// <summary>内存流池</summary>
         public class MemoryStreamPool : Pool<MemoryStream>
         {
             /// <summary>初始容量</summary>

diff --git a/NewLife.Core/Data/Packet.cs b/NewLife.Core/Data/Packet.cs
index 61d075b..8ae7a6d 100644
--- a/NewLife.Core/Data/Packet.cs
+++ b/NewLife.Core/Data/Packet.cs
@@ -2,6 +2,7 @@
 using System.IO;
 using System.Text;
 using System.Threading.Tasks;
+using NewLife.Collections;
 
 namespace NewLife.Data
 {
@@ -203,10 +204,10 @@ namespace NewLife.Data
             if (Next == null) Data.ReadBytes(Offset, Count);
 
             // 链式包输出
-            var ms = new MemoryStream();
+            var ms = Pool.MemoryStream.Get();
             WriteTo(ms);
 
-            return ms.ToArray();
+            return ms.Put(true);
         }
 
         /// <summary>从封包中读取指定数据</summary>
@@ -224,7 +225,7 @@ namespace NewLife.Data
 
             // 链式包输出
             if (count < 0) count = Total - offset;
-            var ms = new MemoryStream();
+            var ms = Pool.MemoryStream.Get();
 
             // 遍历
             var cur = this;
@@ -246,7 +247,7 @@ namespace NewLife.Data
 
                 cur = cur.Next;
             }
-            return ms.ToArray();
+            return ms.Put(true);
 
             //// 以上算法太复杂，直接来
             //return ToArray().ReadBytes(offset, count);

diff --git a/NewLife.Core/IO/IOHelper.cs b/NewLife.Core/IO/IOHelper.cs
index dfd5a93..032f4ba 100644
--- a/NewLife.Core/IO/IOHelper.cs
+++ b/NewLife.Core/IO/IOHelper.cs
@@ -409,7 +409,7 @@ namespace System
             // 如果要读完数据，又不支持定位，则采用内存流搬运
             if (!stream.CanSeek)
             {
-                var ms = new MemoryStream();
+                var ms = Pool.MemoryStream.Get();
                 while (true)
                 {
                     var buf = new Byte[1024];
@@ -420,7 +420,7 @@ namespace System
                     if (count < buf.Length) break;
                 }
 
-                return ms.ToArray();
+                return ms.Put(true);
             }
             else
             {

diff --git a/NewLife.Core/Net/UdpSession.cs b/NewLife.Core/Net/UdpSession.cs
index d80894b..ea4aa94 100644
--- a/NewLife.Core/Net/UdpSession.cs
+++ b/NewLife.Core/Net/UdpSession.cs
@@ -28,8 +28,8 @@ namespace NewLife.Net
         /// <summary>底层Socket</summary>
         Socket ISocket.Client => Server?.Client;
 
-        /// <summary>数据流</summary>
-        public Stream Stream { get; set; }
+        ///// <summary>数据流</summary>
+        //public Stream Stream { get; set; }
 
         private NetUri _Local;
         /// <summary>本地地址</summary>
@@ -94,7 +94,7 @@ namespace NewLife.Net
         public UdpSession(UdpServer server, IPEndPoint remote)
         {
             Name = server.Name;
-            Stream = new MemoryStream();
+            //Stream = new MemoryStream();
             StartTime = DateTime.Now;
 
             Server = server;

diff --git a/NewLife.Core/Serialization/Binary/BinaryPair.cs b/NewLife.Core/Serialization/Binary/BinaryPair.cs
index b471f8f..2ce754b 100644
--- a/NewLife.Core/Serialization/Binary/BinaryPair.cs
+++ b/NewLife.Core/Serialization/Binary/BinaryPair.cs
@@ -6,6 +6,7 @@ using System.Linq;
 using System.Reflection;
 using System.Text;
 using System.Xml.Serialization;
+using NewLife.Collections;
 using NewLife.Reflection;
 
 namespace NewLife.Serialization
@@ -86,14 +87,14 @@ namespace NewLife.Serialization
             else
             {
                 // 准备好名值对再一起写入。为了得到数据长度，需要提前计算好数据长度，所以需要临时切换数据流
-                var ms = new MemoryStream();
+                var ms = Pool.MemoryStream.Get();
                 var old = host.Stream;
                 host.Stream = ms;
                 var rs = host.Write(value, type);
                 host.Stream = old;
 
                 if (!rs) return false;
-                buf = ms.ToArray();
+                buf = ms.Put(true);
             }
 
             WriteLog("    WritePair {0}\t= {1}", name, value);

diff --git a/NewLife.Core/Serialization/Binary/BinaryUnknown.cs b/NewLife.Core/Serialization/Binary/BinaryUnknown.cs
index 1bda34e..caf52ef 100644
--- a/NewLife.Core/Serialization/Binary/BinaryUnknown.cs
+++ b/NewLife.Core/Serialization/Binary/BinaryUnknown.cs
@@ -2,6 +2,7 @@
 using System.IO;
 using System.Reflection;
 using System.Runtime.Serialization.Formatters.Binary;
+using NewLife.Collections;
 
 namespace NewLife.Serialization
 {
@@ -33,11 +34,12 @@ namespace NewLife.Serialization
             // 调用.Net的二进制序列化来解决剩下的事情
             var bf = new BinaryFormatter();
 
-            var ms = new MemoryStream();
+            var ms = Pool.MemoryStream.Get();
             bf.Serialize(ms, value);
 
             Host.WriteSize((Int32)ms.Length);
             ms.CopyTo(Host.Stream);
+            ms.Put();
 
             return true;
         }

diff --git a/NewLife.Core/Web/WebClientX.cs b/NewLife.Core/Web/WebClientX.cs
index eee14d5..d66c260 100644
--- a/NewLife.Core/Web/WebClientX.cs
+++ b/NewLife.Core/Web/WebClientX.cs
@@ -176,7 +176,7 @@ namespace NewLife.Web
                         break;
                 }
 
-                var ms = new MemoryStream();
+                var ms = NewLife.Collections.Pool.MemoryStream.Get();
                 var ns = rs.GetResponseStream();
 
                 ns.CopyTo(ms);
@@ -186,7 +186,7 @@ namespace NewLife.Web
                     ns.CopyTo(ms);
                 }
 
-                return ms.ToArray();
+                return ms.Put(true);
             }
         }