Do not use asio cancel, because it is not portable. It will cause an exception on Windows XP. Just let the socket be closed.

src/net/common/sessiondata.cpp

@@ -32,13 +32,6 @@ SessionData::SessionData(SOCKET sockfd, SessionId id, boost::shared_ptr<SenderIn
 SessionData::~SessionData()
 {
 	m_callback.SignalSessionTerminated(m_id);
-	// We are shutting down, so ignore any error.
-	try
-	{
-		m_socket->cancel();
-	} catch(...)
-	{
-	}
 }
 
 SessionId