typed/buffer.go
func (w *WriteBuffer) DeferBytes(n int) BytesRef {
	return BytesRef(w.deferred(n))
}
func (w *WriteBuffer) DeferBytes(n int) BytesRef {
	return BytesRef(w.deferred(n))
}
// DeferBytes reserves space in the buffer for a fixed sequence of bytes, and
// returns a reference that can be used to update those bytes