balancer: add clarifying note to PickOptions.Header (#2377)

2018-10-15 10:27:54 -07:00
parent 5b2c343e0b
commit 371811880c
1 changed files with 2 additions and 1 deletions
--- a/balancer/balancer.go
+++ b/balancer/balancer.go
@ -155,7 +155,8 @@ type PickOptions struct {
 	// FullMethodName is the method name that NewClientStream() is called
 	// with. The canonical format is /service/Method.
 	FullMethodName string
-	// Header contains the metadata from the RPC's client header.
+	// Header contains the metadata from the RPC's client header.  The metadata
+	// should not be modified; make a copy first if needed.
 	Header metadata.MD
 }