// it also requires the caller to implement the more efficient Size and MarshalToSizedBuffer methods
		encodedSize := uint64(t.Size())
		estimatedSize := prefixSize + estimateUnknownSize(&unk, encodedSize)
		data := memAlloc.Allocate(estimatedSize)

		i, err := unk.NestedMarshalTo(data[prefixSize:], t, encodedSize)
		if err != nil {
			return err
		}

		copy(data, s.prefix)

	{1000, []byte{0x80, 0x00, 0x03, 0xE8}},
	{33554431, []byte{0x81, 0xFF, 0xFF, 0xFF}},
}

func TestSize(t *testing.T) {
	b := make([]byte, 4)
	for i, test := range sizeTests {
		n := encodeSize(b, test.size)
		if !bytes.Equal(b[:n], test.bytes) {
			t.Errorf("%d expected %x, encoded %x", i, test.bytes, b)
		}
		size, n := readSize(test.bytes)
		if size != test.size {