refactor(ui): replace direct Rendering store with MarkWritten() call

- Use `RequestWriter.MarkWritten()` instead of directly storing to `rw.Rendering`
- Update comment to clarify that `Write` records the write instant via `MarkWritten()`
- Remove outdated test assertion for `rendering=true`, as it's now covered by core package tests

Signed-off-by: Johan Lindh <johan@linkdata.se>

Author: linkdata

lib/ui/requestwriter.go

@@ -22,9 +22,10 @@ func (rw RequestWriter) NewUI(ui jaws.UI, params ...any) (err error) {
 	return
 }
 
-// Write records that rendering has started, then writes p to the underlying writer.
+// Write records the write instant (see [jaws.Request.MarkWritten]), then writes p
+// to the underlying writer.
 func (rw RequestWriter) Write(p []byte) (n int, err error) {
-	rw.Rendering.Store(true)
+	rw.MarkWritten()
 	return rw.Writer.Write(p)
 }
 

lib/ui/requestwriter_test.go

@@ -43,9 +43,8 @@ func TestRequestWriter_MethodsAndWidgetHelpers(t *testing.T) {
 	if got := buf.String(); got != "prefix" {
 		t.Fatalf("unexpected write output %q", got)
 	}
-	if !rq.Rendering.Load() {
-		t.Fatal("expected rendering=true after write")
-	}
+	// Write records the write instant via Request.MarkWritten (covered by the core
+	// package's pending-eviction tests); lastWriteNano is unexported here.
 
 	if rw.Initial() == nil {
 		t.Fatal("expected initial request")