Sometimes I write an answer and i don't want to publish automatically i need to make sure my answer is correct and i need to wait more time for some reason Is there a way to save my answer draft? and publish my answer after some time?
There is an automatic mechanism which saves your draft every 45 seconds.
That means you can write your answer and wait 45 seconds before you leave the page, then your draft is saved. When you return to that question you can continue where you left off.
You can find out if it was saved by looking for the
draft saved text below your edit box.
If you need more control of that mechanism then you can use George Edison's awesome Manual draft save script.
Generally just use your regular off-line draft-saving tools (e.g., gedit, vim, etc.). However, in my opinion it is perfectly fine to publish your speculation with a caveat, e.g., "I believe this will work, but I am still in the process of testing it".
This makes sense to me particularly when there are not current solutions that look viable.
You run the risk of being down-voted, but if done in good faith, you will probably get enough counteracting up-votes to end up with positive reputation anyway.