Fix key of field without quoting issue

entry.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"reflect"
 	"runtime"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -138,7 +139,7 @@ func (entry *Entry) WithFields(fields Fields) *Entry {
 				fieldErr = tmp
 			}
 		} else {
-			data[k] = v
+			data[strings.TrimPrefix(strings.TrimSuffix(strconv.Quote(k), `"`), `"`)] = v
 		}
 	}
 	return &Entry{Logger: entry.Logger, Data: data, Time: entry.Time, err: fieldErr, Context: entry.Context}

entry_test.go

@@ -254,3 +254,17 @@ func TestEntryReportCallerRace(t *testing.T) {
 		entry.Info("should not race")
 	}()
 }
+
+func TestEntryWithHardcodedField(t *testing.T) {
+	out := new(bytes.Buffer)
+
+	l := New()
+	l.SetOutput(out)
+
+	l.WithFields(Fields{
+		"animal":  "walrus",
+		"stu\xff": "test\"\xff\xff\xff\xff\x30\x00\x00\x00\x00test\xee\x81\x9a",
+	}).Info("A bug\nwas verified")
+	assert.Contains(t, out.String(), "animal")
+	assert.Contains(t, out.String(), `stu\xff`)
+}