Looking on the internet deeply has found these results:

I will send it to you in early next week. is the most popular phrase on the web.

I will send it to you by early next week. 13 results on the web	I will send it to you in early next week. 14,870,000,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
Mitch, just listen to what Monty says today, and we'll have you out on the floor by early next week. I will definitely finish and hand it over early next week. No Unagi or I will send it back. And I will send it to you tomorrow morning. Let Carrie go and I swear I will send it to you. I will send it to the Ministry of Education. This was a most disturbing report and I will send it to your services. and temperatures will diminish by early next week.	No Unagi or I will send it back. This was a most disturbing report and I will send it to your services. And I will send it to you tomorrow morning. I will need you in early to make up for lost hours. I will definitely finish and hand it over early next week. Let Carrie go and I swear I will send it to you. I will send it to the Ministry of Education. I will need you in early to make up for lost hours.

I will send it to you by early next week.

13 results on the web

I will send it to you in early next week.

14,870,000,000 results on the web

More popular!

Mitch, just listen to what Monty says today, and we'll have you out on the floor by early next week.
I will definitely finish and hand it over early next week.
No Unagi or I will send it back.
And I will send it to you tomorrow morning.
Let Carrie go and I swear I will send it to you.
I will send it to the Ministry of Education.
This was a most disturbing report and I will send it to your services.
and temperatures will diminish by early next week.