Revert "reduce append cycles"

This reverts commit 6ee6667.

slog.go

@@ -129,47 +129,41 @@ func (h *slogJSONHandler) handle(_ context.Context, r slog.Record) error {
 	e := epool.Get().(*Entry)
 	e.buf = e.buf[:0]
 
+	e.buf = append(e.buf, '{')
+
 	// time
 	if !r.Time.IsZero() {
-		e.buf = append(e.buf, (`{"` + slog.TimeKey + `":"`)...)
+		e.buf = append(e.buf, '"')
+		e.buf = append(e.buf, slog.TimeKey...)
+		e.buf = append(e.buf, `":"`...)
 		e.buf = r.Time.AppendFormat(e.buf, time.RFC3339Nano)
-		// level
-		switch r.Level {
-		case slog.LevelDebug:
-			e.buf = append(e.buf, (`","` + slog.LevelKey + `":"DEBUG"`)...)
-		case slog.LevelInfo:
-			e.buf = append(e.buf, (`","` + slog.LevelKey + `":"INFO"`)...)
-		case slog.LevelWarn:
-			e.buf = append(e.buf, (`","` + slog.LevelKey + `":"WARN"`)...)
-		case slog.LevelError:
-			e.buf = append(e.buf, (`","` + slog.LevelKey + `":"ERROR"`)...)
-		default:
-			e.buf = append(e.buf, (`","` + slog.LevelKey + `":"`)...)
-			e.buf = append(e.buf, r.Level.String()...)
-			e.buf = append(e.buf, '"')
-		}
-	} else {
-		// level
-		switch r.Level {
-		case slog.LevelDebug:
-			e.buf = append(e.buf, (`{"` + slog.LevelKey + `":"DEBUG"`)...)
-		case slog.LevelInfo:
-			e.buf = append(e.buf, (`{"` + slog.LevelKey + `":"INFO"`)...)
-		case slog.LevelWarn:
-			e.buf = append(e.buf, (`{"` + slog.LevelKey + `":"WARN"`)...)
-		case slog.LevelError:
-			e.buf = append(e.buf, (`{"` + slog.LevelKey + `":"ERROR"`)...)
-		default:
-			e.buf = append(e.buf, (`{"` + slog.LevelKey + `":"`)...)
-			e.buf = append(e.buf, r.Level.String()...)
-			e.buf = append(e.buf, '"')
-		}
+		e.buf = append(e.buf, `",`...)
+	}
+
+	// level
+	e.buf = append(e.buf, '"')
+	e.buf = append(e.buf, slog.LevelKey...)
+	switch r.Level {
+	case slog.LevelDebug:
+		e.buf = append(e.buf, `":"DEBUG"`...)
+	case slog.LevelInfo:
+		e.buf = append(e.buf, `":"INFO"`...)
+	case slog.LevelWarn:
+		e.buf = append(e.buf, `":"WARN"`...)
+	case slog.LevelError:
+		e.buf = append(e.buf, `":"ERROR"`...)
+	default:
+		e.buf = append(e.buf, `":"`...)
+		e.buf = append(e.buf, r.Level.String()...)
+		e.buf = append(e.buf, '"')
 	}
 
 	// source
 	if h.options.AddSource && r.PC != 0 {
 		name, file, line := pcNameFileLine(r.PC)
-		e.buf = append(e.buf, (`,"` + slog.SourceKey + `":{"function":"`)...)
+		e.buf = append(e.buf, ',', '"')
+		e.buf = append(e.buf, slog.SourceKey...)
+		e.buf = append(e.buf, `":{"function":"`...)
 		e.buf = append(e.buf, name...)
 		e.buf = append(e.buf, `","file":"`...)
 		e.buf = append(e.buf, file...)
@@ -179,9 +173,7 @@ func (h *slogJSONHandler) handle(_ context.Context, r slog.Record) error {
 	}
 
 	// msg
-	e.buf = append(e.buf, (`,"` + slog.MessageKey + `":"`)...)
-	e.string(r.Message)
-	e.buf = append(e.buf, '"')
+	e = e.Str(slog.MessageKey, r.Message)
 
 	// with
 	if b := h.entry.buf; len(b) != 0 {