How to add restricted headers like(expect:100-continue) through postman and interceptor

I am trying to add restricted header(expect-100-continue) to postman post request since I have a huge payload. I did some research and found out that postman ignores restricted headers like(expect) even if you add it to header section.

So I downloaded postman interceptor extension as I read in documentation we can add restricted headers through interceptor, I was able to connect interceptor to postman following documentation but I couldn’t find a way to add that header.

How would we add those restricted headers to postman to test?

Did you add the header in Postman and checked in the console that is was actually not set (wihout the interceptor)?