all: replace uses of ioutil with io and os (#24869)

rpc/http.go

@@ -23,7 +23,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"mime"
 	"net/http"
 	"net/url"
@@ -176,12 +175,12 @@ func (hc *httpConn) doRequest(ctx context.Context, msg interface{}) (io.ReadClos
 	if err != nil {
 		return nil, err
 	}
-	req, err := http.NewRequestWithContext(ctx, "POST", hc.url, ioutil.NopCloser(bytes.NewReader(body)))
+	req, err := http.NewRequestWithContext(ctx, "POST", hc.url, io.NopCloser(bytes.NewReader(body)))
 	if err != nil {
 		return nil, err
 	}
 	req.ContentLength = int64(len(body))
-	req.GetBody = func() (io.ReadCloser, error) { return ioutil.NopCloser(bytes.NewReader(body)), nil }
+	req.GetBody = func() (io.ReadCloser, error) { return io.NopCloser(bytes.NewReader(body)), nil }
 
 	// set headers
 	hc.mu.Lock()

rpc/server_test.go

@@ -22,6 +22,7 @@ import (
 	"io"
 	"io/ioutil"
 	"net"
+	"os"
 	"path/filepath"
 	"strings"
 	"testing"
@@ -70,7 +71,7 @@ func TestServer(t *testing.T) {
 
 func runTestScript(t *testing.T, file string) {
 	server := newTestServer()
-	content, err := ioutil.ReadFile(file)
+	content, err := os.ReadFile(file)
 	if err != nil {
 		t.Fatal(err)
 	}