[VOL-4442] grpc streaming connection monitoring

Change-Id: Id787e94cf28745d36e72f8ed2f5c316312714db4
diff --git a/vendor/google.golang.org/grpc/internal/transport/flowcontrol.go b/vendor/google.golang.org/grpc/internal/transport/flowcontrol.go
index f262edd..97198c5 100644
--- a/vendor/google.golang.org/grpc/internal/transport/flowcontrol.go
+++ b/vendor/google.golang.org/grpc/internal/transport/flowcontrol.go
@@ -136,12 +136,10 @@
 
 // newLimit updates the inflow window to a new value n.
 // It assumes that n is always greater than the old limit.
-func (f *inFlow) newLimit(n uint32) uint32 {
+func (f *inFlow) newLimit(n uint32) {
 	f.mu.Lock()
-	d := n - f.limit
 	f.limit = n
 	f.mu.Unlock()
-	return d
 }
 
 func (f *inFlow) maybeAdjust(n uint32) uint32 {