quick return instead of exception

Author: gusarov

src/River.HttpWrap/HttpWrapClientStream.cs

@@ -136,6 +136,7 @@ private int ReceiveHttp(Stream stream, byte[] buf, int pos, int cnt)
 					var c = stream.Read(_readBuf, _readTo, _readBuf.Length - _readTo);
 					if (c == 0)
 					{
+						return 0;
 						throw new ConnectionClosingException();
 					}
 					_readTo += c;

src/River.HttpWrap/HttpWrapHandler.cs

@@ -43,6 +43,7 @@ private int Unwrap(Stream stream, byte[] buf, int pos, int cnt)
 					var c = stream.Read(_readBuf, _readTo, _readBuf.Length - _readTo);
 					if (c == 0)
 					{
+						return 0;
 						throw new ConnectionClosingException();
 					}
 					_readTo += c;