[feature] stream CloseSend (#2323)

* support stream CloseSend

* move CloseSend into Closer

examples/stream/rpc/client/main.go

@@ -0,0 +1,100 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"time"
+
+	"context"
+
+	proto "github.com/asim/go-micro/examples/v4/stream/rpc/server/proto"
+	"go-micro.dev/v4"
+)
+
+func bidirectional(cl proto.StreamerService) {
+	// create streaming client
+	stream, err := cl.Stream(context.Background())
+	if err != nil {
+		fmt.Println("err:", err)
+		return
+	}
+
+	// bidirectional stream
+	// send and receive messages for a 10 count
+	for j := 0; j < 10; j++ {
+		if err := stream.Send(&proto.Request{Count: int64(j)}); err != nil {
+			fmt.Println("err:", err)
+			return
+		}
+		rsp, err := stream.Recv()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			fmt.Println("recv err", err)
+			break
+		}
+		fmt.Printf("Sent msg %v got msg %v\n", j, rsp.Count)
+	}
+
+	// close the stream
+	if err := stream.Close(); err != nil {
+		fmt.Println("stream close err:", err)
+	}
+}
+
+func serverStream(cl proto.StreamerService) {
+	// send request to stream count of 10
+	stream, err := cl.ServerStream(context.Background(), &proto.Request{Count: int64(10)})
+	if err != nil {
+		fmt.Println("err:", err)
+		return
+	}
+
+	var i int
+
+	// server side stream
+	// receive messages for a 10 count
+	for {
+		rsp, err := stream.Recv()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			fmt.Println("recv err", err)
+			break
+		}
+		i++
+		fmt.Printf("got msg %v\n", rsp.Count)
+	}
+
+	if i < 10 {
+		fmt.Println("only got", i)
+		return
+	}
+
+	// close the stream
+	if err := stream.Close(); err != nil {
+		fmt.Println("stream close err:", err)
+	}
+}
+
+func main() {
+	service := micro.NewService()
+	service.Init()
+
+	// create client
+	cl := proto.NewStreamerService("go.micro.srv.stream", service.Client())
+
+	for {
+		fmt.Println("Stream")
+		// bidirectional stream
+		bidirectional(cl)
+
+		fmt.Println("ServerStream")
+		// server side stream
+		serverStream(cl)
+
+		time.Sleep(time.Second)
+	}
+}