From 38098954f4165eb15a2868e4acbc0c0045cf2e5c Mon Sep 17 00:00:00 2001
From: Lucas Clemente <lucas@clemente.io>
Date: Tue, 12 Jul 2016 15:01:14 +0200
Subject: [PATCH] reduce calls to framer.getFCAllowance

---
 stream_framer.go | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/stream_framer.go b/stream_framer.go
index 178c0be6c..0b277af0a 100644
--- a/stream_framer.go
+++ b/stream_framer.go
@@ -145,11 +145,13 @@ func (f *streamFramer) maybePopNormalFrame(maxBytes protocol.ByteCount) (*frames
 		}
 		maxLen := maxBytes - frameHeaderBytes
 
-		fcAllowance, err := f.getFCAllowanceForStream(s)
-		if err != nil {
-			return nil, err
+		if s.lenOfDataForWriting() != 0 {
+			fcAllowance, err := f.getFCAllowanceForStream(s)
+			if err != nil {
+				return nil, err
+			}
+			maxLen = utils.MinByteCount(maxLen, fcAllowance)
 		}
-		maxLen = utils.MinByteCount(maxLen, fcAllowance)
 
 		if maxLen == 0 {
 			continue