t.Fatal("headers have not been written yet")
	}

	wrap2.WriteHeader(123)
	if !headersAlreadyWritten(wrap2) {
		t.Fatal("headers were written")
	}
}

func TestWriteResponseHeadersNotWritten(t *testing.T) {
	rw := httptest.NewRecorder()
	trw := &trackingResponseWriter{ResponseWriter: rw}

	writeResponse(trw, 299, []byte("hello"), "application/foo")

	resp := rw.Result()