From b6758e67e0126948b3f53e7cfe7699b3b3076213 Mon Sep 17 00:00:00 2001
From: Lucas Clemente <lucas@clemente.io>
Date: Tue, 26 Jul 2016 17:12:42 +0200
Subject: [PATCH] minor stream optimization

---
 stream.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/stream.go b/stream.go
index 57d184b4..a97bacdc 100644
--- a/stream.go
+++ b/stream.go
@@ -169,8 +169,8 @@ func (s *stream) lenOfDataForWriting() protocol.ByteCount {
 
 func (s *stream) getDataForWriting(maxBytes protocol.ByteCount) []byte {
 	s.mutex.Lock()
-	defer s.mutex.Unlock()
 	if s.dataForWriting == nil {
+		s.mutex.Unlock()
 		return nil
 	}
 	var ret []byte
@@ -183,6 +183,7 @@ func (s *stream) getDataForWriting(maxBytes protocol.ByteCount) []byte {
 		s.doneWritingOrErrCond.Signal()
 	}
 	s.writeOffset += protocol.ByteCount(len(ret))
+	s.mutex.Unlock()
 	return ret
 }