Serious question

Where is the science
that says that those who are not vaccinated,
and DO NOT have any symptoms
can be contagious for 3 days BEFORE
they have symptoms and be carriers of the virus?

Show me. NO, I'm not kidding.

I am hearing that people are "hearing this"
and I want the science and if you know where you heard this
and will post it kindly for me, I would appreciate it.
I think it's a load of 💩