})
	testCancel(func() {
		rb.Read([]byte{10: 1})
	})
	testCancel(func() {
		rb.ReadByte()
	})
	testCancel(func() {
		rb.Write(make([]byte, sz))
		rb.Flush()
	})
}

func TestWriteAfterWriterClose(t *testing.T) {
	rb := New(100).SetBlocking(true)

	done := make(chan error)
	go func() {
		defer close(done)
		_, err := rb.Write([]byte("hello"))
		if err != nil {