more comments

transport/transport.go

@@ -169,6 +169,7 @@ type Stream struct {
 	// ctx is the associated context of the stream.
 	ctx    context.Context
 	cancel context.CancelFunc
+	// earlyDone is closed when the final status arrives prematurely.
 	earlyDone chan struct{}
 	// method records the associated RPC method of the stream.
 	method       string