fix when body was set by the user

Author: honfika

Titanium.Web.Proxy/EventArguments/SessionEventArgs.cs

@@ -483,7 +483,6 @@ public void SetRequestBody(byte[] body)
             }
 
             request.Body = body;
-            request.UpdateContentLength();
         }
 
         /// <summary>

Titanium.Web.Proxy/Http/Request.cs

@@ -102,6 +102,11 @@ public bool ExpectContinue
 
         internal override void EnsureBodyAvailable(bool throwWhenNotReadYet = true)
         {
+            if (BodyInternal != null)
+            {
+                return;
+            }
+
             //GET request don't have a request body to read
             if (!HasBody)
             {

Titanium.Web.Proxy/Http/RequestResponseBase.cs

@@ -16,7 +16,7 @@ public abstract class RequestResponseBase
         /// <summary>
         /// Cached body content as byte array
         /// </summary>
-        private byte[] body;
+        protected byte[] BodyInternal;
 
         /// <summary>
         /// Cached body as string
@@ -127,11 +127,11 @@ public byte[] Body
             get
             {
                 EnsureBodyAvailable();
-                return body;
+                return BodyInternal;
             }
             internal set
             {
-                body = value;
+                BodyInternal = value;
                 bodyString = null;
 
                 //If there is a content length header update it
@@ -173,6 +173,11 @@ internal byte[] GetCompressedBody(string encodingType, byte[] body)
 
         internal byte[] CompressBodyAndUpdateContentLength()
         {
+            if (!IsBodyRead)
+            {
+                return null;
+            }
+
             bool isChunked = IsChunked;
             string contentEncoding = ContentEncoding;
 
@@ -219,7 +224,7 @@ internal byte[] CompressBodyAndUpdateContentLength()
 
         internal void UpdateContentLength()
         {
-            ContentLength = IsChunked ? -1 : body?.Length ?? 0;
+            ContentLength = IsChunked ? -1 : BodyInternal?.Length ?? 0;
         }
 
         /// <summary>
@@ -229,7 +234,7 @@ internal void FinishSession()
         {
             if (!KeepBody)
             {
-                body = null;
+                BodyInternal = null;
                 bodyString = null;
             }
         }

Titanium.Web.Proxy/Http/Response.cs

@@ -81,6 +81,11 @@ public bool KeepAlive
 
         internal override void EnsureBodyAvailable(bool throwWhenNotReadYet = true)
         {
+            if (BodyInternal != null)
+            {
+                return;
+            }
+
             if (!IsBodyRead && throwWhenNotReadYet)
             {
                 throw new Exception("Response body is not read yet. " +