Actually you have a choice. You can count it as 2019 income if you want to. That would be simplest and not require any work around on your tax forms.
That said, you can also save it for 2020, if that works out best, for you. You do not need to attach any statements (write a note to the IRS) and you can still e-file.
Report the entire 1099-Misc amount as income. Under Other expenses, claim a deduction for the Jan. rent not received.
