Add a benchmark for streaming calls

rpc/bench_test.go

@@ -8,8 +8,50 @@ import (
 	"capnproto.org/go/capnp/v3"
 	"capnproto.org/go/capnp/v3/rpc"
 	testcp "capnproto.org/go/capnp/v3/rpc/internal/testcapnp"
+	"capnproto.org/go/capnp/v3/std/capnp/stream"
 )
 
+func BenchmarkStreaming(b *testing.B) {
+	ctx := context.Background()
+	p1, p2 := net.Pipe()
+	srv := testcp.StreamTest_ServerToClient(nullStream{})
+	conn1 := rpc.NewConn(rpc.NewStreamTransport(p1), &rpc.Options{
+		BootstrapClient: capnp.Client(srv),
+	})
+	defer conn1.Close()
+	conn2 := rpc.NewConn(rpc.NewStreamTransport(p2), nil)
+	defer conn2.Close()
+	bootstrap := testcp.StreamTest(conn2.Bootstrap(ctx))
+	defer bootstrap.Release()
+	var (
+		futures      []stream.StreamResult_Future
+		releaseFuncs []capnp.ReleaseFunc
+	)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		fut, rel := bootstrap.Push(ctx, nil)
+		futures = append(futures, fut)
+		releaseFuncs = append(releaseFuncs, rel)
+	}
+	for i, fut := range futures {
+		_, err := fut.Struct()
+		if err != nil {
+			b.Errorf("Error waiting on future #%v: %v", i, err)
+		}
+	}
+	for _, rel := range releaseFuncs {
+		rel()
+	}
+}
+
+// nullStream implements testcp.StreamTest, ignoring the data it is sent.
+type nullStream struct {
+}
+
+func (nullStream) Push(context.Context, testcp.StreamTest_push) error {
+	return nil
+}
+
 func BenchmarkPingPong(b *testing.B) {
 	p1, p2 := net.Pipe()
 	srv := testcp.PingPong_ServerToClient(pingPongServer{})