chore(protocol_test): remove usage of ioutil

protocol_test.go

@@ -11,7 +11,6 @@ import (
  "errors"
  "fmt"
  "io"
- "io/ioutil"
  "net"
  "testing"
  "time"
@@ -1480,7 +1479,7 @@ type testConn struct {
 
 func (c *testConn) ReadFrom(r io.Reader) (int64, error) {
  c.readFromCalledWith = r
- b, err := ioutil.ReadAll(r)
+ b, err := io.ReadAll(r)
  return int64(len(b)), err
 }
 func (c *testConn) Write(p []byte) (int, error) {
@@ -1625,7 +1624,7 @@ func benchmarkTCPProxy(size int, b *testing.B) {
 
  }()
  //receive data
- n, err := io.Copy(ioutil.Discard, conn)
+ n, err := io.Copy(io.Discard, conn)
  if n != int64(len(data)) {
  b.Fatalf("Expected to receive %d bytes, got %d", len(data), n)
  }