fix: preserve logger byte reservations

tests/logger/queue_test.go

@@ -267,6 +267,32 @@ func TestQueueStopBeforeStartReleasesBudget(t *testing.T) {
 	}
 }
 
+func TestQueueReleasesSubmittedSizeAfterEntryMutation(t *testing.T) {
+	for _, tc := range []struct {
+		name   string
+		mutate func(*logger.LogEntry)
+	}{
+		{name: "smaller", mutate: func(entry *logger.LogEntry) { entry.RequestBody = nil }},
+		{name: "larger", mutate: func(entry *logger.LogEntry) { entry.RequestBody = []byte("much larger body") }},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			entry := &logger.LogEntry{RequestID: "queued", RequestBody: []byte("body")}
+			q := logger.NewQueue(nil, 2, 2, 1, time.Hour, logger.EstimatedBytes(entry))
+			q.Submit(entry)
+			tc.mutate(entry)
+
+			ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+			defer cancel()
+			if err := q.Stop(ctx); err != nil {
+				t.Fatalf("Stop: %v", err)
+			}
+			if stats := q.Stats(); stats.Bytes != 0 || stats.Failed != 1 {
+				t.Fatalf("stats=%+v", stats)
+			}
+		})
+	}
+}
+
 func TestQueueCanceledStopEventuallyReleasesAllBudget(t *testing.T) {
 	entry := &logger.LogEntry{RequestID: "queued"}
 	q := logger.NewQueue(nil, 32, 32, 1, time.Hour, 32*logger.EstimatedBytes(entry))