Write 6GB+ XML File without In-memory Methods

Excuse me what "necessary"? Sorry, I could not understand this part of your post.

I'm giving you a reasonable friendly advise, and you are kinda playing offense card. It's up to you what you use, but people like myself believe in you and act in assumption that you can use your own brain to get answers, which is always much more valuable. If you need to get spoon-fed, you won't get much, no matter what resource you can use.

Really... sorry for meeting your expectations.

But... what's wrong with Solution 1? This is exactly what you need. Are you going to accept it formally?

Thank you for your understanding.
—SA

All right, thanks for your clarification.

It means that I could have said "is it necessary?", not you. I mean, this was the advice not to limit your request by people who experienced the same problem you did. Addressing to the people who experienced the same problem is not at all necessary. Just the opposite, some people who never experienced that problem just because they saw right approach well before facing the problem, who did not really faced it, are more likely to help.

This is just one example of the case when you don't need people who have had similar problem to help you.
There is nothing snobbish in that (I would prefer this expression), it's just pure logic and addressing to facts of life. If you don't limit your request too much, you can more likely get a useful advice.

Thank you for your understanding.
—SA